Suricata

Instead of having individual sections in different chapters, consolidate those into
one chapter. Would make it easier for users to know where to look for terms,
and can be grown with time.

Related to discussing in https://github.com/OISF/suricata/pull/13174/files/5973ac00d08b410872da8eb51b4fa44182b24fcf#r2109219802

Besides the terms that already exist in chapters such as the Firewall and Exception Policies ones,
also add the term decode -- like parsing, but on the packet level.

Indicate that throughout most of the documentation, inspection and detection are used mostly interchangeably.