Added filtering for PBC requests
Sticky header partial updates:
handling more than one header at a level
expandable/collapsible headers as for PBC request filters

This is a WIP.  Sending to Andy for further review
tree filter controller (missing from previous commits)
Fixed issues with sticky headers where headers outside the viewport were used in header positioning computations (also reverted some prior changes as they resulted in regressions)
Fixed an issue where headers with a height taller than the "scrollaway margin" were disappearing early
Fixed error on blanking date field
WIP - attempting to make clone filters look like originals in all cases
Merge branch 'develop' into feature/pbc-filters

Conflicts:
	src/ggrc/assets/mustache/audits/tree.mustache
Fixed a merge typo
Updated sticky headers to use the original header elements as the sticky ones (using the clones as placeholders)
adding Status in all modal objects
Added related_audits_via_related_responses to related_object mapping
Merge branch 'develop' into feature/mapped_in_audits
Added support for "mapped in audits" to the rest of the relevant object types
Added "Mapped in Audits" header for business object types
Story 60882418: Clone any evidence files that were picked from existing GDrive instances (other folders than the current request)
Added filtered "where object is mapped in Audit" lists for Mapped in Audits
Added read only support for Mapped in Audits (except for Mapped Objects in Responses)
Added initial version of if_helpers (combines multiple helpers into a single conditional helper)
Blocked tree footers from being included for responses that are rendered on non-Audit/Program/Person pages