move 'Compliance Tool' section out of 'Getting Started'

model.base: add method for adding objects to namespaces

See merge request !81

model.base: fix object identifier change + add tests

See merge request !80

model.base: move 'remove by identifier' functionality of NamespaceSet.remove() to new NamespaceSet.remove_by_id()

When changing the identifier (id_short, semantic_id, name or type) of
and object, all namespace sets of the respective namespace are checked
and updated. This may cause an error if the parent namespace has
namespace sets that aren't structured by the attribute that is updated,
causing an error in NamespaceSet.__contains__() or
NamespaceSet.contains_id().

This is fixed by excepting such errors and returning False instead.

model.base: move identifier containment check of NamespaceSet.__contains__() to new NamespaceSet.contains_id()

This fixes an AttributeError raised when calling .upper() on References.

model.base: fix id_short validation

See merge request !78

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.

Merge docs/sphinx_autodocs into improve/V30RC01

See merge request !74

aas.model.provider.AbstractObjectProvider: Remove trailing whitespace from docstring for pycodestyle

This fixes #115

Support for stripped objects has been introduced in
!61
However, the module docstrings were not updated to reflect
the new functionality.