Replace hardcoded paths

[JostMigenda]

[From discussion on a separate PR]

The plugin CemrgApp/Plugins/kcl.cemrgapp.easi/ contains a few hard-coded paths to local directories. We should either update this with a user-supplied path, or remove the plugin, since it appears to be unused at the moment.

Same in CemrgTests.cpp—which has almost 50 hits when searching for /home/or15 (though many are commented out).

Those two files seem to be the only ones in the CemrgApp codebase that are affected.