[confcom] Add a programmatic schema for acipolicygen input

[DomAyre]

We currently have a great markdown document explaining the format, but a programmatic JSON schema would support docs creation, and in code validation from a single source of truth.

We could implement this by defining the json input as data classes in the code, and then generating json schemas and docs from it

[yonzhan]

Thank you for opening this issue, we will look into it.

[DomAyre]

The plan is to define data classes which outline the schema, which we can use in code but also generate JSON schemas/docs from.

I will also update the code that parses other types of input to first parse it into this format before all going to a single policygen function.

In order to have confidence this doesn't break acipolicygen, the first step to to add tests for this function which don't currently exist: #9199

[DomAyre]

Adding these tests uncovered this bug:

• [confcom] Fix issues with --exclude-default-fragments #9198

[DomAyre]

Changing how the ARM template is parsed can lead to variations in the template which aren't functional, for example environment variables can be defined in a different order. Since some tests rely on this order, we should standardise it to avoid breaking tests:

• Sort environment variables in generated polices DomAyre/azure-cli-extensions#5