[RM Ch7] Refresh Ch7 Security

[petorre]

Feedback from GSMA ISAG:

• 7.7.2 Open-source software security: ... feels like the security sections are detached from GSMA FASG recommendations and seem to repeat the work of other bodies. This could lead to a conflict particularly with FS.31 and other recommendations – specifically with duplicated security requirements.
• 7.7.3 Software Bill of Materials: Security text should reference the GSMA document number for the 5G Security Guide in the text body (FS.40). Noting the version referenced is out-of-date (it is now at version 3.0, not version 2.0).
• 7.9.3 United Kingdom (UK): no reference to the UK Telecoms Security Act Code of Practice which covers many of the requirements and is of relevance.