Add GitHub action to build static site

[cthoyt]

Closes #167

This PR adds a new GitHub actions workflow which does the following on a cron job (and optionally on command via the workflow_dispatch option):

1. checks out the master branch
2. installs the local package (plus indra for now, up for discussion)
3. runs the exporter that generates the static site in the docs/ folder
4. makes a commit
5. pushes to the master branch of sorgerlab/famplex
6. dance party

This PR also fixes the display of descriptions on term pages (see ff16d7c).

Discussion

• How to test stuff like this, since it needs to be on master to run?
• Is it okay to run with indra as a requirement?
• What frequency is best for cron? Daily might be overkill - weekly could be better.
• Which party parrot is best?

[bgyori]

• I think installing INDRA isn't a problem but loading the ontology graph might be, due to memory constraints - we'd have to try running the action to see what happens.
• Would it make sense to run the website from another branch and push to that branch instead of master?
• I haven't done anything like this before but is it possible to trigger the action when something is pushed to sorgerlab/master instead of a fixed cron timer? If not, a weekly build would be good.
• I've never seen such a large version of the party parrot, nice!

[cthoyt]

I guess we could give it a shot and see what happens, the only thing to change would be removing the install line for INDRA if it doesn't work.

I've seen other sites that run from a branch instead of master. I find this pretty confusing and opaque.

Yes, we could have it trigger on push instead. That's actually quite simple, and how most testing works anyway. Since most work is done in branches/pull requests then it won't have to run too often. I will do that

See https://cultofthepartyparrot.com/

[cthoyt]

@bgyori It will only run on pushes to master as of b9ea79f. Should we merge this to see what happens?