Trail is now a topology
Path has no foreign key to Trail anymore
Show Trail in menu
Merge remote-tracking branch 'origin/develop' into 370_move_trail_model

Conflicts:
	geotrek/core/filters.py
Rename TopoFilter to TopologyFilter
Move crazy method to TopologyFilter class
Use custom views for Trail

Conflicts:
	geotrek/core/views.py

Conflicts:
	geotrek/core/filters.py
New SQL definition of l_t_sentiers
Show trails as other topologies
Merge branch 'develop' into 370_move_trail_model
Remove mentions of trail field on Path
Fix Trail filter, form and detail pages
Filter by trail in maintenance and infrastructure modules
Remove remaining mentions of trail
Filter private class method instead of static
Update changelog
Migrate existing trails
Remove more specific code
Restore path filter by trail
Add some missing translations