Two warnings, SC2034 and SC2178, pop up very often with the references
- shellcheck handles them poorly and produces a ton of bogus warnings
about them. Silence the warnings and drop most of the "shellcheck
disable" clauses.
That way shellcheck sources some prepared files and learns about some
variables the sourced files define. Thanks to that, we can remove some
of the "shellcheck disable" clauses.
This adds some scripts I have been using for over a year to deal with
the weekly package updates.
It comes with a `README.md` which describes a workflow similar to my
own.
The `sync_packages.sh` and `update_packages.sh` scripts are currently
not used anywhere. The idea behind them was to use them for Github
Action, but that will come as a follow-up PR.
