Generic "update from files" workflow

[gouttegd]

I outlined such a workflow in a comment to a rejected PR a few weeks ago, but I think it deserved its own issue.

Basically, the idea is to allow editors to apply arbitrary changes to the -edit file simply by dropping files into a dedicated directory (e.g. src/ontology/tmp/updates).

When the ontology maintainer runs a make apply-updates workflow:

1. We scan the contents of the src/ontology/tmp/updates directory.
2. For each file in that directory, we apply a logic dependent on the file type:

• if it is a OBO/OWL file, we assume the file contains pre-made axioms ready to be added as they are, and we merge them into the -edit file;
• if it is a TSV file, we assume it is a ROBOT template, we apply the template and merge the result into the -edit file;
• if it is a KGCL file, we apply the instructions it contains to the -edit file (that one in particular would allow removing / changing existing axioms, instead of only adding new ones like the previous two).

Such a workflow could even support “Gsheets workflows” (not that I think that such workflows are a good idea, personally) if we have a convention that a file with a name starting with remote- is supposed to contain a link pointing to the actual update file.

Originally posted by @gouttegd in #1240 (comment)