Move (some) common and NRF models to common-src to unify YAML slicing configuration

Changes

• Moved important common models to common
• Moved NRF models which are used by SMF Profile to common
• Implemented conversion function from YAML to JSON (taken from PCF)
• Implement validate function of Snssai

Refactoring effort

There are a lot of changes here, but mostly I just generated new models with the newest Release 16 (e.g. 16.13 for 29.571) and moved them. It is the starting point of moving all common models (from 29.571) and all NRF models here, because they are being used by all NFs

Forward-Compatibility

If we want to update to Release 17 or 18, we can conveniently generate new models. Our changes (e.g. validation or to_string) can be easily integrated in the new model then using git diff.

Draft Status

There may be more changes, depends on SMF refactoring effort

@tien-thinh.nguyen Note for review: Most classes are 1:1 from openapi-generator, but I have implemented to_string in Snssai, SmfInfo, SnssaiInfoItem and DnnSmfInfoItem