Dockerized dev

[dl-maura]

This is building off of the Blacklight local docker development system, giving you an option to run a local dev using docker.

Fulfills ticket 1443.

To test, follow the readme directions and confirm it works! Recommend squash merging I had typos I had to fix so a lot of commit messages.

[gwiedeman]

This is awesome, and is working great for me. I just made two very minor suggestions to get the old README to jive with the updates.

[marlo-longley]

Hi @dl-maura nice work! This works locally for me.

I would advocate for cleaning up the multiple commits in this PR before a final review/merge. Also not sure where things are at with the testing -- let me know if you want a second pair of eyes.

[seanaery]

Hi @dl-maura -- a fresh pull of this branch and I'm back to getting SQLite errors upon a docker-compose up again (on an M1 Mac). It was definitely working Friday when I tried (with export DOCKER_DEFAULT_PLATFORM=linux/amd64) , so not sure what's different now.

[dl-maura]

Current state: this 'works' but some of the selenium tests are failing, I think because of ports needing to be exposed (the code that is failing is not affected at all by the work here). I am going to speak to a colleague who knows more than I do about Rails tests to see if I can get it worked out next week.