Cleanup ai-core branches

Goal is to recreate a valid master branch.

The current master branch diverged too much from the 2.1_10.10 maintenance branch. It is missing a lot of commits.
It may also contain some commits that were not backported. Those must not be lost.

• start from 2.1_10.10
  https://github.com/nuxeo/nuxeo-ai/tree/2.1_10.10
• trigger a new master
• remove commits/path we don't want
• reapply missing master commits
• in case of conflict, skip and review afterward