MDL-82936 reportbuilder: new APIs for enhancing report rendering.

MDL-82936 reportbuilder: new APIs for enhancing report rendering.

We're introducing two new sets of APIs for both custom and system
reports:

* Report actions allow for the definition of an action to belong
  to the report and be rendered alongside the filters button;
* Report info container allows for the definition of content to
  render between the aforementioned action buttons and the table
  content itself