Merge remote-tracking branch 'origin/nfapi-p7-refactoring' into integration_2024_w48 (!3131)

FAPI P7 Refactoring and unitary test creation

This MR is a follow-up to the work done in !2714 this time separating
the P7 FAPI messages into its own library (nr_fapi_p7).

In the same way, utility functions to copy, free and compare have been
added for each message, as well as an addition function to get the
allocated size for a message, which is used for the messages that can be
too big to fit in a buffer that's allocated in the stack.

Unitary tests have been added for each of the messages, testing
pack/unpack and the utility functions added.