Improve star rating filter

A couple of issues with the new star rating filter in the top bar of the lighttable view.

The first is that, in its default (all selected) state, it draws the eye a bit too much and can be distracting - it's quite bright and high-contrast.

The second is that it is somewhat hard to read at-a-glance. If I select a range of ratings, especially in the middle of the range, I have to look hard to see which stars I've selected. For example:

The main thing I see when I just glance at this control is that two stars are highlighted. But I have to engage extra brain functions to work out which two stars are selected (is it two to three, or four to five?). In the previous interface, I usually used "greater than or equal to" by default so when I saw two stars highlighted in the top bar I instantly knew what that meant without having to think further (two == two or more stars). It's "intuitive" in the way that looking at an analogue clock is. In the new way it's the opposite, in that if I select "two or more stars", I will actually see three stars highlighted. This is hard on my tiny brain.

Start with the star rating filter in the top bar of the lighttable view and review the screenshot and linked pull request for existing context. Define a less distracting default appearance and a selection display that makes the chosen rating range immediately clear; done means both concerns are resolved in the lighttable UI.