Move swift and dxpy into extras

[jtratner]

Follow-on to #143 . Makes swift and dxpy actually optional so people can opt into complex dependencies rather than being forced to use 'em, yay!

Tested this out in a codespace:

@jtratner ➜ /workspaces/stor (move-swift-and-dxpy-into-extras) $ poetry build
@jtratner ➜ /workspaces/stor (move-swift-and-dxpy-into-extras) $ for extratype in dxpy dxpy,swift swift; do rm -rf example-env/ && virtualenv example-env && source example-env/bin/activate && pip install 'dist/stor-4.2.0-py3-none-any.whl['$extratype']' && pip list > $extratype.txt && deactivate; done

New traceback:

Traceback (most recent call last):
  File "/workspaces/stor/stor/dx.py", line 21, in <module>
    import dxpy
ModuleNotFoundError: No module named 'dxpy'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/workspaces/stor/stor/base.py", line 47, in __new__
    cls = utils.find_dx_class(path)
  File "/workspaces/stor/stor/utils.py", line 273, in find_dx_class
    from stor.dx import DXPath, DXCanonicalPath, DXVirtualPath
  File "/workspaces/stor/stor/dx.py", line 25, in <module>
    raise utils.missing_storage_library_exception("dx", e) from e
ImportError: ModuleNotFoundError: No module named 'dxpy'
To use a 'dx' path, stor needs an additional python library. Please specify it as an extra in the installation.
i.e.,: `pip install stor[dx]` or `stor[dx] >= 5` in requirements.txt or `poetry add stor[dx]`.
Alternatively, change an existing pyproject.toml file to specify `stor = {version="5.0", extras = dx}`

And then showed results

`cat dxpy.txt`

@jtratner ➜ /workspaces/stor (move-swift-and-dxpy-into-extras) $ cat dxpy.txt 
Package            Version
------------------ -----------
argcomplete        3.3.0
boto3              1.34.90
botocore           1.34.90
cached-property    1.5.2
certifi            2024.2.2
charset-normalizer 3.3.2
dxpy               0.373.0
idna               3.7
jmespath           1.0.1
pip                24.0
psutil             5.9.8
python-dateutil    2.9.0.post0
requests           2.31.0
s3transfer         0.10.1
setuptools         69.5.1
six                1.16.0
stor               4.2.0
urllib3            2.1.0
websocket-client   0.54.0
wheel              0.43.0

`cat swift.txt`

@jtratner ➜ /workspaces/stor (move-swift-and-dxpy-into-extras) $ cat swift.txt 
Package               Version
--------------------- -----------
boto3                 1.34.90
botocore              1.34.90
cached-property       1.5.2
certifi               2024.2.2
charset-normalizer    3.3.2
debtcollector         3.0.0
idna                  3.7
iso8601               2.1.0
jmespath              1.0.1
keystoneauth1         5.6.0
msgpack               1.0.8
netaddr               1.2.1
netifaces             0.11.0
os-service-types      1.7.0
oslo.config           9.4.0
oslo.i18n             6.3.0
oslo.serialization    5.4.0
oslo.utils            7.1.0
packaging             24.0
pbr                   6.0.0
pip                   24.0
pyparsing             3.1.2
python-dateutil       2.9.0.post0
python-keystoneclient 5.4.0
python-swiftclient    4.5.0
PyYAML                6.0.1
requests              2.31.0
rfc3986               2.0.0
s3transfer            0.10.1
setuptools            69.5.1
six                   1.16.0
stevedore             5.2.0
stor                  4.2.0
tzdata                2024.1
urllib3               2.2.1
wheel                 0.43.0
wrapt                 1.16.0

`cat dxpy,swift.txt`

@jtratner ➜ /workspaces/stor (move-swift-and-dxpy-into-extras) $ cat dxpy,swift.txt 
Package               Version
--------------------- -----------
argcomplete           3.3.0
boto3                 1.34.90
botocore              1.34.90
cached-property       1.5.2
certifi               2024.2.2
charset-normalizer    3.3.2
debtcollector         3.0.0
dxpy                  0.373.0
idna                  3.7
iso8601               2.1.0
jmespath              1.0.1
keystoneauth1         5.6.0
msgpack               1.0.8
netaddr               1.2.1
netifaces             0.11.0
os-service-types      1.7.0
oslo.config           9.4.0
oslo.i18n             6.3.0
oslo.serialization    5.4.0
oslo.utils            7.1.0
packaging             24.0
pbr                   6.0.0
pip                   24.0
psutil                5.9.8
pyparsing             3.1.2
python-dateutil       2.9.0.post0
python-keystoneclient 5.4.0
python-swiftclient    4.5.0
PyYAML                6.0.1
requests              2.31.0
rfc3986               2.0.0
s3transfer            0.10.1
setuptools            69.5.1
six                   1.16.0
stevedore             5.2.0
stor                  4.2.0
tzdata                2024.1
urllib3               2.1.0
websocket-client      0.54.0
wheel                 0.43.0
wrapt                 1.16.0