🏭 Split GHA jobs and extract composite actions

[SimonMarquis]

Main advantages:

• improves GHA readability: less code in the main workflow files
• improves maintainability: composite actions are self contained
• reduces copy/paste mistakes & oversights (e.g. java version was set to 17 and 21)
• slight increase in total build time, but reduces the perceived parallelized time.

Extracted composite actions:

• setup-gradle
• setup-gradle-managed-devices
• setup-gradle-properties
• setup-java
• setup-kvm

Jobs split into more granular groups:

Current workflows

• test_and_apk: :build-logic:convention:check, spotlessCheck, dependencyGuard, dependencyGuardBaseline, verifyRoborazziDemoDebug, recordRoborazziDemoDebug, testDemoDebug, :lint:test, :app:assemble, :app:lintProdRelease, :app-nia-catalog:lintRelease, :lint:lint, :app:checkProdReleaseBadging
• androidTest: connectedDemoDebugAndroidTest, testDemoDebugUnitTest, createDemoDebugCombinedCoverageReport

New workflows

• checks: :build-logic:convention:check, spotlessCheck, dependencyGuard, dependencyGuardBaseline, :app:checkProdReleaseBadging
• assemble: :app:assemble
• lint: :app:lintProdRelease, :app-nia-catalog:lintRelease, :lint:lint
• unit-tests: verifyRoborazziDemoDebug, recordRoborazziDemoDebug, testDemoDebug, :lint:test
• instrumented-tests: connectedDemoDebugAndroidTest, testDemoDebugUnitTest, createDemoDebugCombinedCoverageReport

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For the required checked jobs, this fan-in method can be applied to simplify the required checks configuration.