feat: `avm/res/compute/gallery`: Added UDT applicationsType

[johnlokerse]

Description

This PR adds the applicationsType UDT and updates existing UDTs to follow AVM standards.

Tagging owner: @ReneHezser

Pipeline Reference

Pipeline

Type of Change

• [x] Update to CI Environment or utilities (Non-module affecting changes)
• [x] Azure Verified Module updates:
  • [ ] Bugfix containing backwards-compatible bug fixes, and I have NOT bumped the MAJOR or MINOR version in version.json:
  • [ ] Someone has opened a bug report issue, and I have included "Closes #{bug_report_issue_number}" in the PR description.
  • [ ] The bug was found by the module author, and no one has opened an issue to report it yet.
  • [x] Feature update backwards compatible feature updates, and I have bumped the MINOR version in version.json.
  • [ ] Breaking changes and I have bumped the MAJOR version in version.json.
  • [x] Update to documentation

Checklist

• [x] I'm sure there are no other open Pull Requests for the same update/change
• [x] I have run Set-AVMModule locally to generate the supporting module files.
• [x] My corresponding pipelines / checks run clean and green without any errors or warnings

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[johnlokerse]

Thank you for your contribution. I added some small comments.

Thanks! Implemented the comments. Could you re-check it to see if it's as expected?