Rename BaseGenerator to GeneratorBase

[OutlawAndy]

Why?

BaseGenerator sounds like it's a generator itself, but it's not. It also shows up in the list of available generators for the consumer app, which it shouldn't.

What Changed

What changed in this PR?

• Rename BaseGenerator to GeneratorBase
• move GeneratorBase out of rolemodel/generators directory
• improve bin/new_generator output
• clean up bin/recreate_current_example generator
• update github PR template
  • there is almost never a reason to include screenshots
  • I'm moving gem version management out of PRs and into GH Actions

Pre-merge checklist

• Update relevant READMEs
• Run bin/bump_version or bin/bump_version --patch

Screenshots

[justwiebe]

Is the generator going to be able to be run a second time if the inflections are setup? Or don't inflections affect gems?

[OutlawAndy]

just testing on the example app, host application inflections do not affect gem file loading. Which I think makes sense. Rails inflections affect constant look up because they're tied into the Rails autoloader, but RMR's generators are not loaded by the Zeitwerk autoloader. They are just added to the Ruby FILE_PATH