Pymtl3

- Add several new test utility components to stdlib
- Improve run_sim and run_vector_sim, refactor plugin options
- Refactor all the tests to use the improved test utility functions
- Add finalize_verilator to run_sim and vector sims
- Rework several parts of RTLIR to accelerate translation
- Drastically improved verilator import performance and compilation time
- Accelerated the dynamic compilation of ff_flip

- Bug fixes
- Translatable constant-size slicing
- Throw deprecation errors for deprecated primitives
- Support connecting a constant struct to a signal
- Implement hypothesis strategy for bitstructs and improve bits strategy
- passes/ folder major refactoring
- Tick function refactoring. Add eval_combinational to top.

- The vcd generation pass had some bugs and cannot handle some cases correctly. I took a pass to fix the bugs and refactored the code.
- Merge in Kaishuo's text-based waveform pass
- The ast caching caches the _value_ it gets from the globals/closure but it really shouldn't do so because two instances of the same class can have different closure content based on the parameter. I changed ast caching to cache the variable name and look them up on a per-instance basis during elaboration.