Added caching to Gradle steps in GitHub Actions

[Mithrandir21]

What kind of change does this PR introduce?

Feature: This PR will add a caching and caching retrieval step to all GitHub Actions steps that involve Gradle.
Caches will make builds faster by not requiring Gradle to download and configure all dependencies for each build.
The cache 'hit' and 'miss' logic is robust and should work well across builds.

What is the current behavior?

No caching is currently implemented in the GitHub Actions steps where Gradle is involved.

What is the new behavior?

Caches will automatically be created in the GitHub Actions 'caches' section, that will be attempted reused during builds.

Additional context

Link to GitHub Actions repo:
Gradle-cache-action

Additionally, there are a lot of settings that can be configurated if and when needed.

[jan-tennert]

Hey, thank you for this PR! We already have Gradle Caching via the setup-gradle plugin:

supabase-kt/.github/workflows/build.yml

Lines 24 to 28 in b740029

	- name: Setup Gradle
	uses: gradle/actions/[email protected]
	with:
	cache-encryption-key: ${{ secrets.GRADLE_ENCRYPTION_KEY }}
	cache-read-only: false

Currently, the master branch writes to the cache and all PRs and other branches read from the cache.
If you have any suggestions or improvements regarding the current approach, feel free to leave your feedback!