Certify Caracara and its Underlying Libraries Against Python 3 Deprecations

[ChristopherHammond13]

Caracara and Caracara-Filters utilise functionality that will be removed in a future version of Python 3. This ticket serves to ensure we are covered.

The Python 3.13 announcement covers what is due to be removed soon.

• datetime.utcnow() is pending removal in a future version of Python 3.
• datetime.utcfromtimestamp() is pending removal in a future version of Python 3.
• Remove setuptools dependence, if possible, as this is no longer bundled with Python.
• Many other features are deprecated, so we need to go through the code and make sure we don't use anything else pending removal.

[ChristopherHammond13]

In order to migrate to importlib.metadata (and therefore deprecate setuptools), Caracara will only support Python 3.8 upwards as of this release.