Some further massaging for Alpine v3.20

Updating to alpine v3.20

sr.ht packages fix

The gunicorn scripts were catching way too many exceptions and crashing.
I've replaced them with cronjobs to restart the core services on regular
intervals.

Alpine 3.19

Updates to many packages, including several which can be dropped from
vendoring.

Some updates top the Makefile recipes.

Many tips for future me in the README.

Initial commit