add device base protocol

A protocol class should be added to ophyd_devices/utils to describe the bare minimum device interface, something along the lines of

from typing import Protocol, runtime_checkable

@runtime_checkable
class BECDeviceBase(Protocol):

    def stage(self):
        pass

    def unstage(self):
        pass

    def read(self):
        pass

    def describe(self):
        pass

    def read_configuration(self):
        pass