Update ubiquity_motor to use different serial port lib

[rohbotics]

Looks like the serial library we are currently using https://github.com/wjwwood/serial is not really being maintained, and there is no noetic release for it. We should probably move off of it to something like boost asio, or drop the possibility of windows support completely by using the syscalls directly.

[rohbotics]

Note that this is less urgent now that we have our own build of wwjwood's serial in our tree.