Remove concatenation used to create view text / tooltip for date searchers

Date searchers' view html is constructed by concatenating i18n keys such as navigator.filter.duedate.after, navigator.hidden.search.request.summary.date.ago. This concatenation makes assumptions about grammar that are true for english but not necessarily true for other languages.

Change so date searcher view html text is always constructed using i18n keys that are full sentences, not concatenations of multiple subkeys.