Issue #13 and issue #61 p1

Implemented Activity detail Edit/creation
90%, "other links" needs to be implemented, but I think doing a custom element to manage a list of links can be reused for the Original Post selection too.

The code works, but it got a bit messy and would be a better idea to create a new controller to manage, at least the singleActivity Edit

OT. Sorry I'm late.. got some fighting to do with the tabs and core-pages selection
I think it might be a good idea; limiting hardcoded metadata in the code is always good.
I think the structure for AGs and how they are used, need optimization (ex. remove used in Metadata, if a field has a label is used; otherwise hide it) before pushing on the backend.