feat: seserialize EngineeringUnits from symbolic name

[alvskar]

Add Deserialize to units, similar to ObjectType and PropertyIdentifier, to enable using the newtypes directly instead of a u16 and for readability.

Deserialize can in theory be added to all the enums here by putting it in the macro but I assume this was decided against for a reason.

Ran cargo test -p bacnet-types --features serde as well as the checks listed under Development.

[jscott3201]

I'm going to hold this open for a few days until I get this next release fully put together. I hope to have that by end of week and that should clear the issue log as well. Once all those are rolled in I'll look at this and the overall serialization and deserialization work on the library. I have been changing some types under the hood lately so it will be easier to do this off the 1.0.0 base.