Search/Filter UI Improvements

[ivaniesta14]

I find the current implementation of the Search/Filter UI a bit clunky for the following reasons:

• It covers content: words at the top of the word list, and half of the selection word's UI.
• The popup animates in, which takes time before I can start filtering.
• There's no incremental search, meaning I need to confirm my query before the list is filtered.
• The popup closes itself upon confirming a query, which, together with the two points above, means a typo in the query takes a non-insignificant amount of time to correct.
• Confirming the query triggers a full UI reload of the whole window, even when the query has not changed. For some reason, this makes the PolyGlot window stop being maximized if it was previously.
• The search/filter button disappears or takes a while to display the popup after changing scenes (eg. to the word generator section). Might be caused by SrcLexicon's ctor.

A way the first four points could be addressed is by having two textboxes (one for local words and another for constructed ones) that filter the word list accordingly as text is typed into them. (Compare with chrome/firefox's Ctrl+F searchbox)

As for the fifth point, it might be worth looking into ScrLexicon.runFilter as there seem to be repeated calls to ScrLexicon.populateLexicon that may cause further issues.

In case it matters, I'm running the 2023-02-26 beta version under windows 10.