Refactor TemplateView class into TemplateAbstractView so we
only have one class that display template thumbnails and not
a separate for folders and another for files. This will let
us in the future be able to display file system hierarchies in
case of the remote repositories and simplify the view handing
logic.

Change-Id: Iafc246eeff4c50c12ac9ebec9fe95dcc84991e9e