assets: requirejs exclude option

* Adds support for exclusion of files in RequireJS builds, to prevent
  files from being included multiple times. (closes #2411)

* Enables more aggressive compression for UglifyJS.

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>
base: requirejs improvements

* Several improvements for better requirejs compliance.

Signed-off-by: Javier Martin Montull <javier.martin.montull@cern.ch>
workflows: harvesting description template fix

* Reverts back to "<strong>" tags from "<h5>" that
  cause display problems.

* Fixes identation.

Signed-off-by: Georgios Papoutsakis <georgios.papoutsakis@cern.ch>
communities: featured community addition

* Adds featured community.

Signed-off-by: Adrian Pawel Baran <adrian.pawel.baran@cern.ch>