Automate ABNF to python namespace patterns

[ahouseholder]

In #898, we added a new ABNF file src/ssvc/utils/ssvc_namespace_pattern.abnf that was used to generate the namespace regex patterns in src/ssvc/utils/patterns.py. However, this conversion was a one-shot static event.

I'd like us to be able to dynamically read the .abnf file and have that populate the items in patterns.py automatically at run time. I believe this is possible using library methods from abnf-to-regex.

[bernhardreiter]

Added https://github.com/aas-core-works/abnf-to-regexp/issues/44 to fix the repetition regex difference in upstream first.