Add chapter for CISOs

[Gerrit91]

References #57.

Write new sections specifically for CISOs, touching the following topics:

• Artifact Signing and Verification
• RBAC concept (when MEP-4 arrived): which roles do we support and how access is granted / revoked
• Cryptography: which ciphers do we support and recommend?
• Network topology: how is the tenant and network seperation accomplished (explained in CISO terms)
• Communication matrix
• Used technologies and protocols
• Remote access: what is our recommendation? what is the requirement for metalctl machine console to function properly?
• Integration checks: CIS-Benchmark on operating system level
• Patch and Releasemanagement: how are patches and releases categorized, carried out (processual doc), release vector, SBOM