Consolidate GA files?

[bpbond]

The GitHub Actions leeyabot and test-coverage have very similar setups, both needing R, libcurl, and a few packages. Maybe consolidate them into a single yaml file? That would save on GA resources.

[bpbond]

lint is also similar.

[kdorheim]

It also looks like there might be a way to cache builds/environments that way we would only need to build C++ once then pass to google tests and also build R Hector once the pass to leeyabot/code coverage testing

[kdorheim]

On that note we should figure out which GA need to be run every PR/ semi-regularly to catch dependency changes are they're any GA that could be manually triggered (does leeya bot need to run every time or could it be manually triggered when the PR is ready for review)?