Add support for read/write unsigned value from bytearray

[LoicGRENON]

Hello,

I added get_uint/set_uint and get_udint/set_udint to add support for read/write for respectively uint (2bytes) and udint (4 bytes) values from bytearray.

get_usint/set_usint already exists.

[LoicGRENON]

BTW, I implemented this following the same way get_usint/set_usint was done.
I think it might be maybe clearer and easier to maintain to just add an "unsigned" parameter to get_int, get_dint, get_sint and their respective set_* functions and to set the struct format character (signed or unsigned) accordingly rather than copying the same lines multiple time.

Thus, for example, get_uint(bytearray_: bytearray, byte_index: int, _int: int) would call get_int(bytearray_: bytearray, byte_index: int, _int: int, unsigned: Optional[bool]=True)

Do you want me to do such reformating of the functions ?