[V3.1] Change PathType to be of Type xs:anyURI

[s-heppner]

Previously, PathType was matched towards
RFC 8089, however this posed several problems,
such as basyx-python-sdk#72.

In aas-specs#299,
the proposed solution is to make PathType of type xs:anyURI.

Fixes #303
Fixes #330

Depends on #317

[s-heppner]

Currently, the check is failing due to two tests:

• assert not v3_1.matches_xs_any_URI("http://datypic.com#f% rag"): Here I'm a bit out of my depth.
• assert not v3_1.matches_xs_any_URI("http://datypic.com#frag1#frag2"): I've scanned the RFC and could not find it stated anywhere that there is only one fragment allowed (even though it would seem sensible to me).

I'm relatively certain I used the correct URI regex (from here). Can someone help me debug this please?

[s-heppner]

We've acidentally created quite a mess here, so I will close this PR and open new ones instead. Still let me try to document what went wrong here and what we should do instead:

• Path_type is not technically xs:anyURI, rather it is "conforming to RFC 2396" see here.
• matches_xs_any_uri, in this branch is implemented as RFC 3986, an RFC which specifies URI, but is not the RFC used in XSD 1.0, the XSD version used in the AAS. xs:anyURI is specified as "as defined by [RFC 2396], as amended by [RFC 2732]" see here.

Therefore, we now have two things to do:

1. Add a matches_RFC_2396 function and use that in Path_type
2. Adapt matches_xs_any_uri method to use RFC 2396 as ameneded by RFC 2732 (and therefore add RFC 2732 to abnf_to_regexp