Adds option to suppress PR validations by adding ‘prValidation’ to the ‘suppressNotifications’ array.

Workaround for #4061

Closes #4047

Closes #4045

Restores GitLab optimization but with caching and pagination fixes.

Co-authored-by: Lukas Eipert <leipert@users.noreply.github.com>

https://docs.gradle.org/current/dsl/org.gradle.api.artifacts.dsl.DependencyHandler.html#N17198

This reverts commit 9779d77e.

1. `findPr` also includes the `source_branch` API parameter which
shortens execution time considerably
2. `getPrList` also filters `author_id` for the renovate's user

All ts files have to have an `import` or `export` because of
`isolatedModules` flag.

Closes #3969