MINOR: cli: add a function to look up a CLI service description

This function will be useful to check if the keyword is already registered.
Also add a define for the max number of args.

This will be needed by a next patch to fix a bug and will have to be
backported.

(cherry picked from commit a51a1fd17420a96bb766afbae354e041fc9e1d9b)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit b2239a79344a24e0e04aaa159020e4681aadf631)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit fce9e8164b7d305eea87cd4a95b133f8cf0369cf)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit e1085688a8b701e072f5f76b7b7d89339d45e476)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
3 files changed