* Linkingstate Refactor, and displaying link info in rightpanel
Big refactor to LinkingState
Collects descriptive/user-facing labels into FilterState
Unifies/cleans up some logic
Adds LinkTypeDescription, a string enum which can be used
to easily switch/case between various cases of linking, and
codifies the logic in one place (currently only used for linkInfo)
Adds Link info to creator panel, near SelectBy dropdown
Bugfix: Disables linking from Attachment columns
Bugfix/Behavior change: changed linking with empty RefLists to better
match behavior of refs.
for context: Linking by a blank Ref filters to show records with a
blank value for that Ref. Previously this didn't work with RefLists.
Linking from a blank refList would show no records
(except in some cases involving summary tables)
Fixed this so that linking by a blank val consistently means "show
all records where the corresponding col is blank"