Short description of changes

• Use apt --no-install-recommends avoid installation of unneeded packages.
• Android:
  • Drop git (Github's image already contains it)
  • Drop gradle (this is downloaded anyway)
  • Use headless JDK/JRE -- we don't start GUI apps during build

CHANGELOG: Autobuild: Improved build preparation performance.
(Changelog entry should probably be merged with other Autobuild-related entries later)

Context: Fixes an issue?

Speed up build, save resources.

Does this change need documentation? What needs to be documented and how?

No.

Status of this Pull Request

Ready.

What is missing until this pull request can be merged?

Reviews.

Checklist

• I've verified that this Pull Request follows the general code principles
• I tested my code and it does what I want
• My code follows the style guide
• I waited some time after this Pull Request was opened and all GitHub checks completed without errors.
• I've filled all the content above