Enforce mandatory tags for all tagging supported resources

My requirements are:
- Enforce few mandatory tags (say `ApplicationName`, `ApplicationOwner`, `SupportContact`, `Environment` & `CostCenter`) to all tagging supported resources. cfn-guard should raise error if any of these tags are found missing.
- Developers can add any number of tags other than the mandatory tags. cfn-guard should not fail if such tags are defined.

Below shown is a sample ruleset that I used to validate the mandatory tags for VPC.
```
AWS::EC2::VPC Tags == /.*"Key":"Environment".*/ << the mandatory Tag: Environment is not specified
AWS::EC2::VPC Tags == /.*"Key":"ApplicationName".*/ << the mandatory Tag: ApplicationName is not specified
AWS::EC2::VPC Tags == /.*"Key":"SupportContact".*/ << the mandatory Tag: SupportContact is not specified
AWS::EC2::VPC Tags == /.*"Key":"ApplicationOwner".*/ << the mandatory Tag: ApplicationOwner is not specified
AWS::EC2::VPC Tags == /.*"Key":"CostCenter".*/ << the mandatory Tag: CostCenter is not specified
```
By evaluating a CFT which contains only tag keys `Service`, `Name` and `ApplicationName`, using this above ruleset, I received the below output.
```
[VPC] failed because [Tags] is [[{"Key":"Service","Value":"VPC"},{"Key":"Name","Value":"DemoVPC"},{"Key":"ApplicationName","Value":"webapp"}]] and the mandatory Tag: ApplicationOwner is not specified
[VPC] failed because [Tags] is [[{"Key":"Service","Value":"VPC"},{"Key":"Name","Value":"DemoVPC"},{"Key":"ApplicationName","Value":"webapp"}]] and the mandatory Tag: CostCenter is not specified
[VPC] failed because [Tags] is [[{"Key":"Service","Value":"VPC"},{"Key":"Name","Value":"DemoVPC"},{"Key":"ApplicationName","Value":"webapp"}]] and the mandatory Tag: Environment is not specified
[VPC] failed because [Tags] is [[{"Key":"Service","Value":"VPC"},{"Key":"Name","Value":"DemoVPC"},{"Key":"ApplicationName","Value":"webapp"}]] and the mandatory Tag: SupportContact is not specified
```

Got two questions here:
1. I have used regex in ruleset to validate tags. Is there any other method suggested for checking the existence of mandatory tags?
2. As per my understanding, cfn-guard currently supports only adding rulesets for each resource type individually. Is there a way to apply this rule set globally for all resources?

No implementation file or test is named in the issue. Start by tracing cfn-guard's rule evaluation and resource-type handling, then determine how mandatory-tag checks and extra tags should work across all supported resources; done means missing required tags fail with useful errors while additional tags remain accepted.

Written by the indexing model from the issue text.