FTP parser command lookup
The FTP parser should use mpm when looking for commands instead of performing a linear search over the command coordinates with squashed case.
Updated by Jeff Lucovsky 3 days ago
Also, address this comment from the FTP logging PR https://github.com/OISF/suricata/pull/3967#discussion_r302236153
" Ok. but then could output-json-ftp.c call some new parsing function in app-layer-ftp.c ?
This way, we will defer parsing until needed and the parsing will be in app-*.c files"