Get rid of `distutils_forwardport.py` A.S.A.P.

For Python 3.12 support, we currently have the distutils_forwardport.py file to provide forward compatibility. This is a temporary measure to keep our framework up-and-running while our dependencies update. As soon as we can, we should get rid of this overhead.

We should - at least - reevaluate our dependencies before the next IPv8 release. If this file cannot be removed before our next release, it should be included in our setup:

py-ipv8/setup.py

Line 16 in d95b11c

py_modules=['ipv8_service'],

Actually, the apispec module seems to have removed distutils from its source since version 6.0.0. Simply manually setting this version, as the minimum version, in our own requirements.txt may be enough to resolve this.

Edit: pip will not allow this:

ERROR: Cannot install -r requirements.txt (line 5) and apispec>=6.0.0 because these package versions have conflicting dependencies.

The conflict is caused by:
    The user requested apispec>=6.0.0
    aiohttp-apispec 2.2.3 depends on apispec<4.0 and >=3.0.0