Optionally remember visible columns / positions

[petebankhead]

Support storing visible columns and positions in the user preferences.

This should be off by default and only active if a Preferences object is provided by the main application. The reason is that a user could potentially run multiple applications on their computer that all use the log viewer - and the preferences should be application-specific.

[Rylern]

Is this still relevant? Should I be working on it?

[petebankhead]

I think ignore it for now, but leave the issue open - I'm currently extracting the way QuPath handles persistent preferences so that it no longer relies on lots of other QuPath dependencies. Maybe we can use it later.

An alternative (and perhaps better) thing to do would be to expose in the public API a way to access the visible columns. Then the host can decide if/how to make those values persistent.