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:

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