cache: move cache invalidation from web handler to post push hook We need the post push hook anyway ... and having the cache invalidation here will also work for ssh pushes in the future. The name log_push_action is thus no longer spot-on. That might change later, but requires some care as it also is used directly as hook name. Note that having cache invalidation in the hook will do that debug logging no longer will appear in the server log. Based on a patch by Dominik Ruf.

# requirements.txt file for use as "pip install -r requirements.txt" as a
# readthedocs compatible alternative to "pip install -e ." which is a working
# alternative to "setup.py develop" which doesn't work with Mercurial 3.7
.