feat(ModelArts): add a data source to get the list of ModelArts model…

[liwanting0517]

… templates

What this PR does / why we need it:

Which issue this PR fixes:
(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged)
fixes #xxx

Special notes for your reviewer:

Release note:

PR Checklist

• Tests added/passed.
• Documentation updated.
• Schema updated.

Acceptance Steps Performed

=== RUN   TestAccDatasourceModelTemplates_basic
=== PAUSE TestAccDatasourceModelTemplates_basic
=== CONT  TestAccDatasourceModelTemplates_basic
--- PASS: TestAccDatasourceModelTemplates_basic (28.53s)
PASS

[Zippo-Wang]

/lgtm

[github-actions]

Cannot apply the lgtm label because Error: Zippo-Wang is not included in the reviewers role in the OWNERS file and is not an organization member or collaborator