todo.sr.ht: normalize init scripts

Split out core.sr.ht migrations in post-upgrade

Make local redis service optional

Add extra gunicorn args to *.init

Add -openrc, fix sources for todo.sr.ht

Fix more indentation issues

Update man.sr.ht.post-upgrade

Also moves alembic dependency to py3-srht

Update todo.sr.ht.post-upgrade

Tweaks to the todo.sr.ht package

Initial pass on todo.sr.ht package