Az.Subscription not included when installing Az Module. Must be installed manually.

## Description
Az.Subscription is not included when you run Install-Module Az

## Steps to reproduce

```powershell

``` Install-Module Az
``` New-AzSubscription etc
``` Command unrecognised
``` Install-Module Az.Subscription

## Environment data
Name Value
---- -----
PSVersion 5.1.19041.1
PSEdition Desktop
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0...}
BuildVersion 10.0.19041.1
CLRVersion 4.0.30319.42000
WSManStackVersion 3.0
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1

Name Value
---- -----
PSVersion 7.0.3
PSEdition Core
GitCommitId 7.0.3
OS Microsoft Windows 10.0.19041
Platform Win32NT
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1
WSManStackVersion 3.0

## Module versions

ModuleType Version Name ExportedCommands
---------- ------- ---- ----------------
Script 1.9.4 Az.Accounts {Disable-AzDataCollection, Disable-AzContextAutosave, Enab...
Script 1.1.1 Az.Advisor {Get-AzAdvisorRecommendation, Enable-AzAdvisorRecommendati...
Script 1.3.0 Az.Aks {Get-AzAksCluster, New-AzAksCluster, Remove-AzAksCluster, ...
Script 1.1.4 Az.AnalysisServices {Resume-AzAnalysisServicesServer, Suspend-AzAnalysisServic...
Script 2.1.0 Az.ApiManagement {Add-AzApiManagementApiToGateway, Add-AzApiManagementApiTo...
Script 1.1.0 Az.ApplicationInsights {Get-AzApplicationInsights, New-AzApplicationInsights, Rem...
Script 1.4.0 Az.Automation {Get-AzAutomationHybridWorkerGroup, Remove-AzAutomationHyb...
Script 3.1.0 Az.Batch {Remove-AzBatchAccount, Get-AzBatchAccount, Get-AzBatchAcc...
Script 1.0.3 Az.Billing {Get-AzBillingInvoice, Get-AzBillingPeriod, Get-AzEnrollme...
Script 1.4.3 Az.Cdn {Get-AzCdnProfile, Get-AzCdnProfileSsoUrl, New-AzCdnProfil...
Script 1.6.0 Az.CognitiveServices {Get-AzCognitiveServicesAccount, Get-AzCognitiveServicesAc...
Script 4.4.0 Az.Compute {Remove-AzAvailabilitySet, Get-AzAvailabilitySet, New-AzAv...
Script 1.0.3 Az.ContainerInstance {New-AzContainerGroup, Get-AzContainerGroup, Remove-AzCont...
Script 1.1.1 Az.ContainerRegistry {New-AzContainerRegistry, Get-AzContainerRegistry, Update-...
Script 1.1.0 Az.DataBoxEdge {Get-AzDataBoxEdgeJob, Get-AzDataBoxEdgeDevice, Invoke-AzD...
Script 1.10.1 Az.DataFactory {Set-AzDataFactoryV2, Update-AzDataFactoryV2, Get-AzDataFa...
Script 1.0.2 Az.DataLakeAnalytics {Get-AzDataLakeAnalyticsDataSource, New-AzDataLakeAnalytic...
Script 1.2.8 Az.DataLakeStore {Get-AzDataLakeStoreTrustedIdProvider, Remove-AzDataLakeSt...
Script 1.0.0 Az.DataShare {New-AzDataShareAccount, Get-AzDataShareAccount, Remove-Az...
Script 1.1.0 Az.DeploymentManager {Get-AzDeploymentManagerArtifactSource, New-AzDeploymentMa...
Script 1.0.0 Az.DesktopVirtualization {Disconnect-AzWvdUserSession, Get-AzWvdApplication, Get-Az...
Script 1.0.2 Az.DevTestLabs {Get-AzDtlAllowedVMSizesPolicy, Get-AzDtlAutoShutdownPolic...
Script 1.1.2 Az.Dns {Get-AzDnsRecordSet, New-AzDnsRecordConfig, Remove-AzDnsRe...
Script 1.3.0 Az.EventGrid {New-AzEventGridTopic, Get-AzEventGridTopic, Set-AzEventGr...
Script 1.6.0 Az.EventHub {New-AzEventHubNamespace, Get-AzEventHubNamespace, Set-AzE...
Script 1.6.1 Az.FrontDoor {New-AzFrontDoor, Get-AzFrontDoor, Set-AzFrontDoor, Remove...
Script 1.0.2 Az.Functions {Get-AzFunctionApp, Get-AzFunctionAppAvailableLocation, Ge...
Script 3.6.0 Az.HDInsight {Get-AzHDInsightJob, New-AzHDInsightSqoopJobDefinition, Wa...
Script 1.1.0 Az.HealthcareApis {New-AzHealthcareApisService, Remove-AzHealthcareApisServi...
Script 2.5.0 Az.IotHub {Add-AzIotHubKey, Get-AzIotHubEventHubConsumerGroup, Get-A...
Script 2.2.0 Az.KeyVault {Add-AzKeyVaultCertificate, Update-AzKeyVaultCertificate, ...
Script 1.0.0 Az.Kusto {Add-AzKustoClusterLanguageExtension, Add-AzKustoDatabaseP...
Script 1.3.2 Az.LogicApp {Get-AzIntegrationAccountAgreement, Get-AzIntegrationAccou...
Script 1.1.3 Az.MachineLearning {Move-AzMlCommitmentAssociation, Get-AzMlCommitmentAssocia...
Script 1.1.0 Az.Maintenance {Get-AzApplyUpdate, Get-AzConfigurationAssignment, Get-AzM...
Script 1.1.0 Az.ManagedServices {Get-AzManagedServicesAssignment, New-AzManagedServicesAss...
Script 1.0.2 Az.MarketplaceOrdering {Get-AzMarketplaceTerms, Set-AzMarketplaceTerms}
Script 1.1.1 Az.Media {Sync-AzMediaServiceStorageKey, Set-AzMediaServiceKey, Get...
Script 2.1.0 Az.Monitor {Get-AzMetricDefinition, Get-AzMetric, Remove-AzLogProfile...
Script 3.4.0 Az.Network {Add-AzApplicationGatewayAuthenticationCertificate, Get-Az...
Script 1.1.1 Az.NotificationHubs {Get-AzNotificationHub, Get-AzNotificationHubAuthorization...
Script 2.3.0 Az.OperationalInsights {New-AzOperationalInsightsAzureActivityLogDataSource, New-...
Script 1.3.1 Az.PolicyInsights {Get-AzPolicyEvent, Get-AzPolicyState, Get-AzPolicyStateSu...
Script 1.1.2 Az.PowerBIEmbedded {Remove-AzPowerBIWorkspaceCollection, Get-AzPowerBIWorkspa...
Script 1.0.3 Az.PrivateDns {Get-AzPrivateDnsZone, Remove-AzPrivateDnsZone, Set-AzPriv...
Script 2.12.1 Az.RecoveryServices {Get-AzRecoveryServicesBackupProperty, Get-AzRecoveryServi...
Script 1.2.1 Az.RedisCache {Remove-AzRedisCachePatchSchedule, New-AzRedisCacheSchedul...
Script 1.0.3 Az.Relay {New-AzRelayNamespace, Get-AzRelayNamespace, Set-AzRelayNa...
Script 2.5.1 Az.Resources {Get-AzProviderOperation, Remove-AzRoleAssignment, Get-AzR...
Script 1.4.1 Az.ServiceBus {New-AzServiceBusNamespace, Get-AzServiceBusNamespace, Set...
Script 2.2.0 Az.ServiceFabric {Add-AzServiceFabricClientCertificate, Add-AzServiceFabric...
Script 1.2.0 Az.SignalR {New-AzSignalR, Get-AzSignalR, Get-AzSignalRKey, New-AzSig...
Script 2.10.0 Az.Sql {Get-AzSqlDatabaseTransparentDataEncryption, Get-AzSqlData...
Script 1.1.0 Az.SqlVirtualMachine {New-AzSqlVM, Get-AzSqlVM, Update-AzSqlVM, Remove-AzSqlVM...}
Script 2.6.0 Az.Storage {Get-AzStorageAccount, Get-AzStorageAccountKey, New-AzStor...
Script 1.3.0 Az.StorageSync {Invoke-AzStorageSyncCompatibilityCheck, New-AzStorageSync...
Script 1.0.1 Az.StreamAnalytics {Get-AzStreamAnalyticsFunction, Get-AzStreamAnalyticsDefau...
Script 1.0.0 Az.Support {Get-AzSupportService, Get-AzSupportProblemClassification,...
Script 1.0.4 Az.TrafficManager {Add-AzTrafficManagerCustomHeaderToEndpoint, Remove-AzTraf...
Script 1.11.0 Az.Websites {Get-AzAppServicePlan, Set-AzAppServicePlan, New-AzAppServ...

## Debug output

Doesn't apply

## Error output
New-AzSubscription: The term 'New-AzSubscription' is not recognized as the name of a cmdlet, function, script file, or operable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.