Board seed2 dfm eval euro

[ohmtech-rdi]

This PR adds support to the Seed2 DFM Eurorack evaluation board, for both the firmware and simulator.

Note
There is a crackling noise on audio channels 3 & 4.
This is potentially a libDaisy bug for which a PR exists here.
We will still merge our branch, as this is considered degraded quality but not a blocker.

Todo:

• Make look closer to actual hardware
• Measure audio levels and make sure ±5V is mapped to/from ±1 for both inputs and outputs
• Add board test to github CI