Reduce Docker Image Size

[HeliosLHC]

Reduces standard Docker image size from ~3.2 GiB to ~1.2 GiB

This PR does the following to reduce image size:

1. Reduce .git directory size in final image
   • Performs in-place shallow clone by keeping only the HEAD commit and pruning unlinked objects
   • Drops .git repository pack files from 800 MiB to roughly 30 MiB
   • .git is kept as it (supposedly) is read at runtime in yacyBuild.properties:ReleaseStub (YaCy's Docker ReleaseStub is entirely broken. #566)
2. Set CHMOD permissions during multi-stage copy
   • Docker BuildKit now supports --chmod and --chown parameters for the COPY function
   • The separate COPY and chown commands are now merged to avoid duplicating the 1 GiB /opt/yacy_search_server directory due to the permission changes
3. Base Image for OS dependencies
   • An additional base image build stage was created to avoid re-installing common OS dependencies in appbuilder and final stages

[Orbiter]

I will look into it soon!

[Orbiter]

great work 👍 thank you!