Address post-merge Docker Compose cleanup issues

[migurski]

Tom H identifies a few desired changes in #2409 (review):

• Investigate alternative to Postgres sleep
• Update checkout to v2
• Investigate bootsnap-related pollution in Rails setup files
• Move DB functions to either lib or share
• Determine if a DB password is needed when using trust auth
• Investigate whether yarnpkg install can move under bundle exec

I’ll look at each of these in a follow up PR and determine which needs a followup change vs. just an explanation.

[tomhughes]

The good news is that it all seems to work using podman-compose in place of docker-compose in Fedora 33.

[mmd-osm]

Re " Move DB functions to either lib or share" : /changes endpoint was removed yesterday, we don't need those DB functions anymore.

[tomhughes]

Also #3082 has bumped the checkout action version.

[gravitystorm]

Re " Move DB functions to either lib or share" : /changes endpoint was removed yesterday, we don't need those DB functions anymore.

I know you'll have seen my comment, but just for other people's reference, we still need the function for the migrations: #2409 (comment)