Specifically handle space permissions related to blogs and templates

Currently, blog and template related space permissions are migrated as global rights on the whole space or discarded. This is less than ideal, we can definitely migrate at least some of them on the specific Blog and Template spaces.

More specifically, after this change, MANAGE_TEMPLATES will be migrated as EDIT and DELETE on the Templates spaces, and REMOVEBLOG as DELETE and EDITBLOG as EDIT on the blog space.