[ARM] az ts : Add UiFormDefinition file support to TemplateSpecs for GA (05/04)

[detienne20]

Awaiting: Azure/azure-sdk-for-python#18297 and #18142

Description

This PR bumps up the API version of TemplateSpecs and adds support for supplying an (optional) uiDefiniton file to az ts [create | update] operations. These are the final changes for Template Specs GA.

Testing Guide

az ts create -g testRG --name TemplateSpecName -v 2.0 -l WestUS --template-file
        templateSpec.json --version-description "Less simple template spec" --ui-definition-file
        templateSpecUiDefinition.json

Update:

az ts update -g ExistingRG --name ExistingName -v 3.0 -f updatedTemplate.json --display-name
        "New parent display name" --description "New parent description" --version-description "New
        child description" --ui-defintion-file updatedUiDefinition.json

[zhoxing-ms]

@detienne20 Could you please fix those CI issues?

[zhoxing-ms]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[Juliehzl]

LGTM for core change