Optionally support LZO via workspaces

[milesgranger]

Replaces #51 and will close #41

Blocked by PyO3/pyo3#1444

Can optionally support LZO and maintain MIT license by packaging that as a separate wheel/distribution and then attempting to import and assign it as a submodule into cramjam.lzo if the user has chosen to install it. However, presently pyclass objects cannot be used across packages; python thinks they are different objects. What that means for us, is

>>> from cramjam import Buffer
>>> from cramjam import lzo  # same as `import cramjam_lzo as lzo`, fails if the user hasn't installed `cramjam_lzo` separately. 

# thinks it can't be converted into a type it actually is
>>> lzo.compress(Buffer(b'bytes'))
Traceback (most recent call last):
  File "<input>", line 1, in <module>
    lzo.compress(Buffer(b'bytes'))
TypeError: 'Buffer' object cannot be converted to 'Union[bytes, bytearray, numpy, File, Buffer]'

# cramjam_lzo gives back a Buffer, which isn't evaluated  to be the same as cramjam.Buffer
>>> out = lzo.compress(b'bytes')
>>> out
cramjam.Buffer(len=14)
>>> isinstance(out, Buffer)
False
>>>