Universal/split project 20.2 autosplit

[hdb-unity]

Purpose of this PR

This PR copies scenes from UniveralGraphicsTest into UniversalGraphicsTest_2D, UniversalGraphicsTest_Foundation, UniversalGraphicsTest_Lighting, UniversalGraphicsTest_Terrain, UniversalGraphicsTest_PostPro.

The aims are to enable better collaboration by separating test projects by team, or at least by concern. Also, to reduce iteration time and CI resource load by allowing developers to more easily run tests relating to the areas of their code changes; instead of running the entire suite each run locally or in CI. The entire suite can and should then be run after iteration to give the full coverage.

This PR lands split projects into master branch.

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Testing status

Manual Tests: What did you do?

• Run split projects in CI
• Run original project in CI
• Run split projects locally on MacOS
• Tested backport process from these split projects to universal/split-project-20.1 and universal/split-project-19.3
• Reverted changes commit to UniversalGraphicsTest project (it should NOT be changed by this PR)

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Comments to reviewers

• CI jobs should continue to use UniversalGraphicsTest after this PR
• This PR should not change any code outside of TestProjects
• This PR should not change any projects in TestProjects, except UniversalGraphicsTest_2D, UniversalGraphicsTest_Foundation, UniversalGraphicsTest_Lighting, UniversalGraphicsTest_Terrain, UniversalGraphicsTest_PostPro
• There are tasks to complete after this PR (as discussed with reviewers)

[theopnv]

Wouldn't it be simpler to have the expression trigger expression: 'pull_request.target eq "<TARGET_BRANCH>" AND NOT pull_request.draft AND pull_request.changes.any match ["com.unity.render-pipelines.universal/**/*", "TestProjects/UniversalGraphicsTest/**/*"] AND NOT pull_request.push.changes.all match ["*.md", "**/*.md", "doc/**/*", "**/Documentation*/**/*"]' here instead of duplicated in the 5 projects?