* Refactor: test_named_ints_flag_names
Shorten test and clarify behavior using binary numbers.
* Introduce plain flag_names function
This replicates the NamedInts functionality as plain function.
* Refactor FeatureFlag to use IntFlag
Replace NamedInts implementation with IntFlag enum and plain flag_names
function.
Related #2273
* Refactor FirmwareKind to use IntEnum
- Move general FirmwareKind to common module.
- Replace NamedInts implementation with IntEnum.
- Harden related HIDPP 1.0 get_firmware test.
Related #2273
* Refactor CID_GROUP, CID_GROUP_BIT to use IntEnum
Related #2273