debug: more details hook failing loggin

vcsserver: implement set head ref and optimize deletion of filenodes

git: allow setting symbolic ref for repos without master branch. fixes #5663

caches: small naming refactor to fix tests.

caches: fixed issue with exception on handling non-ascii cache keys.

git: handle archive generation crash case when submodules are present.

caches: allow regional per repo caches, and invalidate caches via a remote call.

version: bumped to 4.27.0

merged default into stable

caches: updated logging and some timings