Move Template loading and Imageprocessing to mixin Rationale: 1) Template loading is a process used by many components. As such it makes sense to parametrize the URL and centralize loading. 2) Imageprocessing has to be done after each template is loaded on the client As such it makes sense to centralize that. To make handling easier, each (1) and (2) is in an independend Promise to make chaining of calls easier to read.