feat(manager/gradle): add support for Kotlin import directives

[Churro]

Changes

Adds functionality to resolve variables that are referenced via Kotlin import statements.

This PR adds a parser pattern for import statements and stores the corresponding object declarations, classes, etc. If variables cannot be resolved in the local or global context, it is checked whether they were imported by assembling a matching location. The order of checking (local context first) is important because variables could be overwritten after importing.

Context

• Gradle dependencies are not found in combination with "import" #25373

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests but ran on a real repository, or
• Both unit tests + ran on a real repository

Test repo: renovate-demo/25373-renovate-gradle-issue#2

[renovate-release]

🎉 This PR is included in version 37.35.0 🎉

The release is available on:

• GitHub release
• 37.35.0

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