BindControl doesn't deal with "dark mode" very well

[emersonrp]

There are more than a few places where the app does wx.Colour(x,x,x) or "wx.WHITE" or the like where instead it should be pulling things from SystemSettings in order to honor the light / dark mode setting.

[emersonrp]

Hmm this suffered a little scope creep, trying to catch wx.EVT_SYSCOLOURS_CHANGED and re-color everything. This has proven to be a bit of a headache as handlers for that event are being lied to by the wx "IsDark()" method, at least on Linux. Also, wx's set of predefined system colors is a bit anemic, and finding "light grey" analogs for when we're in dark mode is going to have to be a little hamfisted, assuming it can be made to work at all.

Also wxpython 4.3 is in the cooker, which will use wxWidgets 3.3, which has some dark-mode-specific improvements / hacks, so maybe this wants to wait for that.

[emersonrp]

This is mostly good in the 'darkmode' branch, though it's all turned off for Windows since Win11 is such a dumpster fire. In any case, it's a lot of changes but is quite a bit smarter and better looking in dark and light modes in Linux land, at least. Need to test MacOS still.