Big cleanup

[davidsiaw]

Motivation: https://www.notion.so/2023-06-15-Credit-Card-Transaction-Issues-Medium-32fc2c9d510344acb49c8df67877c141

This PR is a big cleanup. Addresses a few problems:

• duplicated dockerfiles
• copypasta with arguments used by hats but not by any other project
• remove obsolete versions
• remove the original rails-base. Older projects (basically all inactive) that still used the old rails-base can continue using them:
  • hats-tester
  • viras
  • new-relic-account
• supply-chain disruption (this reduces the frequency at which we download new dependencies, protecting us from temporary rubygem disruption, yanks and takeovers, also opens up the possibility of testing the image by itself)

This PR adds:

• updated workflow files (now we can specify the dockerfile, so newer versions which do not need new dockerfiles do not need a new dockerfile to be created.)
• refactored dockerfiles (and only need to create a new one for compatibility with newer versions)
• new rails-base (so we don't go downloading everytime)
• parameters in workflow matrix

This is just the first part. The next part will be to modify HATS to use these build images.

[degikko]

@baka-san can you help us review this PR, please?