Refactor App Config tsp

[catalinaperalta]

Refactor code to use aliases and templates for shared code.

[openapi-pipeline-app]

Next Steps to Merge

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• ❌ This is the public specs repo main branch which is not intended for iterative development.
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• ❌ This PR has at least one breaking change (label: BreakingChangeReviewRequired).
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• ❌ The required check named TypeSpec Validation has failed. Refer to the check in the PR's 'Checks' tab for details on how to fix it and consult the aka.ms/ci-fix guide

[openapi-pipeline-app]

Generated ApiView

Language	Package Name	ApiView Link
Java	azure-data-appconfiguration	https://apiview.dev/Assemblies/Review/b3f8e6d8c8354d94bbabd3695ecccadf?revisionId=4e0307cbc96042adad038611a048a618
JavaScript	@azure-rest/azure-appconfiguration-rest	https://apiview.dev/Assemblies/Review/11269592fa87434aacdbdbdb2f585c16?revisionId=4b3371cf31ee4940932fbab6fd6db68b
TypeSpec	AppConfiguration	https://apiview.dev/Assemblies/Review/ddf3033f47d446378a1102f03ca97892?revisionId=0189f3567142483d801e0dbeec3a6469

[azure-sdk]

API change check

APIView has identified API level changes in this PR and created following API reviews.

Microsoft.AppConfiguration