Skip all the things

[raghubetina]

I am proposing some changes to the default railsrc file (which I think we should rename from fd to something like adp for "appdev project" — we should eventually make a different fd rc file and app template for regular, firstdraft projects).

I think it would be nice if we can remove some clutter from early projects; folders for things that we'll never use like channels and webpacker.

Since we skip javascript via webpacker, I think we'll need to update the template to add Sprockets back:

https://stackoverflow.com/questions/55213868/rails-6-how-to-disable-webpack-and-use-sprockets-instead

I also stopped skipping system tests, because I believe the recommended path from RSpec is to use them:

https://medium.com/table-xi/a-quick-guide-to-rails-system-tests-in-rspec-b6e9e8a8b5f6

We should transition our tests to this new style.