Azure Spring Cloud buildservices REST API missing

Hi I have look the in [Bicep doc for Azure Spring Cloud](https://docs.microsoft.com/en-us/azure/templates/microsoft.appplatform/spring/buildservices/builders?tabs=bicep), there are doc for Builders but not for the parent buildService. It is because such [REST API](https://docs.microsoft.com/en-us/rest/api/azurespringcloud/build-service/list-build-services) to create buildservices is missing.

As a consequence it is not possible deploy buildServices with Bicep :

```sh
resource buildService 'Microsoft.AppPlatform/Spring/buildServices@2022-03-01-preview' = {
name: 'string'
parent: azurespringcloud
properties: {
kPackVersion: '0.5.1'
resourceRequests: {
cpu: '200m'
memory: '4Gi'
}
}
}

resource buildagentpool 'Microsoft.AppPlatform/Spring/buildServices/agentPools@2022-03-01-preview' = {
name: 'string'
parent: buildService
properties: {
poolSize: {
name: 'S1'
}
}
}

// https://docs.microsoft.com/en-us/azure/spring-cloud/how-to-enterprise-build-service?tabs=azure-portal#default-builder-and-tanzu-buildpacks
resource builder 'Microsoft.AppPlatform/Spring/buildServices/builders@2022-03-01-preview' = {
name: 'string'
parent: buildService
properties: {
buildpackGroups: [
{
buildpacks: [
{
id: 'tanzu-buildpacks/java-azure'
}
]
name: 'java'
}
]
stack: {
id: 'tanzu-base-bionic-stack' // https://docs.pivotal.io/tanzu-buildpacks/stacks.html
version: '1.1.49'
}
}
}

resource builds 'Microsoft.AppPlatform/Spring/buildServices/builds@2022-03-01-preview' = {
name: 'string'
parent: buildService
properties: {
agentPool: 'string'
builder: 'string'
env: {}
relativePath: 'string'
}
}
```

Start with the linked Azure Spring Cloud build-service REST API and the Bicep resource documentation, then locate the corresponding API specification in this repository. Done means the parent buildServices REST resource is represented alongside its builders, agentPools, and builds resources so the documented Bicep deployment is supported.

Written by the indexing model from the issue text.