Fix url for editing taxon
Fix for the edit and create menu items in the taxonomy tree

When clicking edit in the context menu of the taxonomy tree, the browser is redirected to
the edit view of the taxon. Browser should not follow the api route, but the admin route.

Also fix an error in handle create: upon success a taxon object is returned, so id should be called
on the returned object.
Generate API key for any user who accesses the backend

This is needed for API requests (i.e. taxons editing) that require authentication to the API.
Use jsuri within taxonomy.js for smarter URI manipulating

Kinda related to #2604