fix: run aurweb ssh commands and git scripts in virtualenv

Adjust bash wrapper scripts to activate our python virtualenv:
Script execution is triggered from ssh / git. These wrapper scripts then call python scripts created by poetry.

We should make sure that this happens within our venv. (aurweb issue #450)

Previously this was done by using poetry run.... However, using poetry is costly and adds some delay.
Instead of using poetry, we can just activate our venv and then execute our scripts.

Fixes: b15ac838

roles/aurweb/templates/aurweb-git-auth.sh.j2

 #!/bin/bash
-exec "{{ aurweb_dir }}/.venv/bin/aurweb-git-auth" "$@"
+cd "{{ aurweb_dir }}"
+source .venv/bin/activate
+exec aurweb-git-auth "$@"