Replacing postcard with encdec

[ryan-summers]

This PR replaces postcard with encdec. encdec is more suitable for our precise storage requirements.

I tested this with my current Booster and confirmed that my settings were retained. I also updated parameters and verified that they stuck

I have a PR for the encdec changes needed at ryankurte/rust-encdec#2

[jordens]

Can't there be a generic impl encode/decode for IntoPrimitive/(try) FromPrimitive?
Otherwise looks good to me.
Would encdec instead of serde have been nicer for minimq?

[ryan-summers]

Can't there be a generic impl encode/decode for IntoPrimitive/(try) FromPrimitive? Otherwise looks good to me.

Yeah, we likely can. I wonder if a blanket impl would be considered a trait impl on foreign types though? Or did you mean adding the blanket impl to encdec directly? That might be more complicated

Would encdec instead of serde have been nicer for minimq?

Maybe (probably)? It's hard to say for sure without trying it. Serde was definitely a bit awkward with minimq and other wire protocols and has a few hacky workarounds to the restrictive serde data model. It would be an interesting investigation to try out the Encode/Decode API instead.

[jordens]

Sure. It would need to be in encdec or num_enum. I would have thought that generic impl to be simple. Why would it be complicated?

[jordens]

Anyway. This discussion above can also be resolved independently.

[ryan-summers]

I spawned an issue in ryankurte/rust-encdec#3 for that discussion. It would be nice to have a derive for simple enums for sure.