Aas-core3.0rc02

Non-breaking changes:

* Fix verifications to check for falsy matches (25)
* Fix ``is_xs_date*`` to match first (24)
* Deprecate for Python 3.6 (23)
* Minor fixes in the documentations (22, 21, 20, 19, 18, 16)

* Sync naming with the published schemas for V3RC02 (13)

Please see the pull request for more details. We had to synchronize the naming in aas-core-codegen and aas-core-meta with the published JSON, XML and RDF+SHACL schemas. To maintain the backwards compatibility of code generated by aas-core-codegen, we have to re-name some of the classes and enumerations to unpythonic names such as ``DataTypeDefXsd`` (instead of ``DataTypeDefXSD``).

* Fix escaping in XML serialization.

Notably, ``&`` was mistakenly escaped to ``&amp`` instead of ``&``.
* Fix issues in verification of dates and other XML data types:

* We checked ``matches_*(value) is not None``, while ``matches_*`` returns a boolean.
Therefore, the checks against the patterns were outright ignored in the code.

* We fix the verification of ``xs:float`` for infinity.
This means that overflows are now correctly detected if the value is not a proper ``INF``.

* We disallow floating-point numbers in exponents in ``xs:float`` and ``xs:double``,
see also: [aas-core-meta b2d1230].

* We disallow ``+INF`` as plus sign is not allowed in XML, see also [aas-core-meta a8e6621].

[aas-core-meta b2d1230]: https://github.com/aas-core-works/aas-core-meta/commit/b2d1230
[aas-core-meta a8e6621]: https://github.com/aas-core-works/aas-core-meta/commit/a8e6621

* Initial version, ready for the very first review