readme: link basyx-python-sdk

See merge request !84

- return NotImplemented if other type than AdministrativeInformation

examples: change AAS submodel reference keys to local=True

See merge request !83

...so the AASX Package Explorer can find the submodels.
Also change the ComplianceTool test files accordingly.

README.md: Update Features, Project Structure and License

See merge request !76

Documentation for v2.0.1

See merge request !77

model.base: fix id_short validation

See merge request !79

This commit backports 445b1d8f from
fix/id_short_validation.

In RegEx, the `$` asserts the end of a string or line. When used in
re.match() it asserts the end of the string by default, unless the last
character is a newline symbol (`\n`). Then it asserts the end of the string
*before* the newline. Thus the first regex check doesn't filter valid
id_shorts ending in a newline, which it should.
See https://docs.python.org/3.9/library/re.html#index-2

Using re.fullmatch() instead fixes this issue, making the `^` and `$`
unnecessary as well.

Next to adding a test for this behaviour this commit also simplifies the
check for an alphabetical character at the start of the id_short.
And although both checks could also be merged into one, they are left
separate to be able to report more accurate errors.

docs/source/compliance_tool: Remove cli from the autodocumentation since the documentation of it is already done by argparsing

aas.compliance_tool.cli: Extract the argparsing into a separate function to enable using it in the automatic documentation