Improve performance

As discussed yesterday, the wellen transition made performance slightly worse, we should work on improving that

@ekiwi1 I have added a wiki page on how to measure performance here https://gitlab.com/surfer-project/surfer/-/wikis/Performance%20measurement

In general, drawing performance is OK, but the CLI is very very slow if many waves are loaded. On cpu.vcd with

show_performance redraw
module_add cpu_test_harness.cpu_0

framerate drops a ton when the CLI is open. I'll try to get a flamegraph out of that