Remove & rewrite eurorack-pmod/tmds_encoder verilog dependencies

[vk2seb]

There are some small verilog dependencies remaining, that should be ported to Amaranth.

• gateware/vendor/dvi: contains a TMDS encoder used for video output
• gateware/deps/eurorack-pmod: contains sample calibration, I2S driver, I2C state machine for LEDs + touch sensing.
• VexRiscV is also a non-amaranth dependency, however I tried both Sentinel and Minerva soft-core CPUs (amaranth projects) and unfortunately the performance/area simply is not up to par with Vex yet. So this dependency will stay for the foreseeable future.

Particularly the eurorack-pmod dependency should be ported soon as:

• It shares a lot of functionality with the SoC's I2C driver that could be combined, to reduce LUT usage.
• The ADC/DAC calibration should be performed by the SoC by twiddling some registers. For this it makes sense to have all that logic in pure Amaranth.