Proposal to use BearType to do argument validation

[km-64]

There's this interesting library for performing runtime checking called beartype: https://beartype.readthedocs.io/en/latest/.

I thought it could be used to express some of the more specific constraints in a more declarative way in something like SimDevice, particularly the __check_* methods called from __post_init__ and __check_parameters. I can make a PR with what this could look like.

I see that this package doesn't have any required dependencies, only optional ones (pyserial, aiohttp), so adding beartype would mean adding one required dependency.

[janiversen]

We do not want dependencies unless absolutely requiered.

Only depending on pyserial is one of the strong features of pymodbus.