applet.interface.better_la: a more performant logic analyzer

[anuejn]

This PR implements a more performant logic analyzer applet. Performance is still not great but much better than with the event analyzer based one. It would be very nice to add DDR support for capture & maybe a faster capture clock domain for more accurate timing. However, it is unclear if that actually makes sense based on the short captures I am already getting with this. Maybe USB lag-spikes are the issue here, but that needs further investigations.

I am very happy to take any suggestions on the code style & would be happy to work on it so that this could one day live upstream since i believe that this would also be valuable to many other people

[wanda-phi]

The loose fixes here look like they should be in their own PRs?

[whitequark]

Maybe USB lag-spikes are the issue here, but that needs further investigations.

They are and this is why compression is needed.