DeviceRef inherits from str which leads to confusion on the client

[oliwenmandiamond]

When using the BlueapiClient, if I check the avaliable methods for a device, it will give me the following results:

>>> devs.ew4000
Device(ew4000)
>>> devs.ew4000.
devs.ew4000.capitalize()    devs.ew4000.index(          devs.ew4000.isspace()       devs.ew4000.removeprefix(   devs.ew4000.splitlines(
devs.ew4000.casefold()      devs.ew4000.isalnum()       devs.ew4000.istitle()       devs.ew4000.removesuffix(   devs.ew4000.startswith(
devs.ew4000.center(         devs.ew4000.isalpha()       devs.ew4000.isupper()       devs.ew4000.replace(        devs.ew4000.strip(
devs.ew4000.count(          devs.ew4000.isascii()       devs.ew4000.join(           devs.ew4000.rfind(          devs.ew4000.swapcase()
devs.ew4000.encode(         devs.ew4000.isdecimal()     devs.ew4000.ljust(          devs.ew4000.rindex(         devs.ew4000.title()
devs.ew4000.endswith(       devs.ew4000.isdigit()       devs.ew4000.lower()         devs.ew4000.rjust(          devs.ew4000.translate(
devs.ew4000.expandtabs(     devs.ew4000.isidentifier()  devs.ew4000.lstrip(         devs.ew4000.rpartition(     devs.ew4000.upper()
devs.ew4000.find(           devs.ew4000.islower()       devs.ew4000.maketrans(      devs.ew4000.rsplit(         devs.ew4000.zfill(
devs.ew4000.format(         devs.ew4000.isnumeric()     devs.ew4000.model           devs.ew4000.rstrip(
devs.ew4000.format_map(     devs.ew4000.isprintable()   devs.ew4000.partition(      devs.ew4000.split(

When the only methods which should be available to the user are the ones we expose e.g model I think is the only one that should be available so they can check the device bluesky protocols. These extra methods come from class DeviceRef inheriting str and is rather confusing. It is done this way so that when passing the "device" to the plan, the device is treated as the device name for the server to lookup.

Acceptance Criteria

• DeviceRef no longer inherits from str.

[tpoliaw]

This was originally done to make the json serialization straightforward as it is handled by the requests library where we can't change behaviour. A possible approach to this would be to handle the json serialization on our side and pass the string to the request as data. We could then use a default handler to support DeviceRef types.