CREATE EXTENSION without superuser access

I have an app that would benefit from being able to use pg_partman rather than doing it's own ad-hoc partition management.

Unfortunately, some of the places where the app needs to run don't have root access to the database server filesystem, so I can't install the extension in the postgresql extensions directory.

I could get all the pg_partman functionality by modifying the extension SQL script to remove the extension functionality and installing the functions in it manually, but then I can't take advantage of the extension features for backups, config tables, upgrades and so on - and it's probably not going to interact well if someone does a "create extension pg_partman" in the database.

Is there any way to install an extension either from a SQL connection or from a user-defined directory instead of .../extensions?

(And if not, is there a TODO here?)

Cheers,
Steve