static: modal binding element filter addition

* Adds an optional jQuery filter parameter to the modal binding function; this
is useful, for example, when binding after an AJAX request for skipping already
bound elements.

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
requirements: pymongo addition

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>