Load templates from the model's location #140
Description
For model specific templates, it may make sense to have them in the same location (e.g. git repository) as the model itself. The model explorer currently expects the templates to be regular files in a location known at startup time. It should additionally be possible to load templates from wherever the model itself was loaded from, possibly by reusing its FileHandler.
Also see related issue #138, for the ability to specify multiple template locations.