CLOSES#212
PR to restructure apheleia to make it more modular and improve some of
the separation of concerns. Before merging we should make sure that we
don't reintroduce the issues from #181.
* Fix brittany installation, needed the `--reorder-goals` argument to be
added so that a version that was not the latest version could be
installed so that it was compatible with the base lib version shipped
with Ubuntu 20.04. We'll upgrade to 22.04 eventually (before it falls
out of LTS). Ref: https://github.com/radian-software/apheleia/pull/221
* Add a `make fmt-build-common` target which allows tagging a docker
image containing just the base software and not any formatters, to make
it easy to debug formatter installation manually.
* Update `apheleia-ft` to also run formatter tests when any files
affecting a formatter are changed, which includes the installation
script, the sample input/output, and also any scripts (e.g.
`apheleia-phpcs`) that it uses. We don't have any logic that will run
all formatter tests at once, because that is unwieldy. That can be done
manually if making a big change.
* Update to actions/checkout@v4 from v2 because the older one was listed
as deprecated.
* Print full stacktraces when `apheleia-ft` fails with an Elisp error.
Moves the bulk of apheleia.el into a new apheleia-core.el file and move
formatter definitions and mode-associations into a new
apheleia-formatters.el file. The end user experience should be
unchanged. Loading `apheleia.el` will still load everything load
everything, just like it used to.
