op-mode: T6424: ipsec: honor certificate CN and CA chain during profile generation

In e6fe6e50a5c ("op-mode: ipsec: T6407: fix profile generation") we fixed
support for multiple CAs when dealing with the generation of Apple IOS profiles.

This commit extends support to properly include the common name of the server
certificate issuer and all it's paren't CAs. A list of parent CAs is
automatically generated from the "PKI" subsystem content and embedded into the
resulting profile.

(cherry picked from commit d65f43589612c30dfaa5ce30aca5b8b48bf73211)