DOC: pattern: pattern organisation schematics
MINOR: pattern/cli: Update used terms in documentation and cli

This patch replace the word <name> by the word <file>. This word defines
the (string) returned by show "map/acl". This patch also update
documentation to explain how is composed the map or acl identifier.
MINOR: cli: remove information about acl or map owner.

The string <display> contain all the owners of the displayed pattern.
The message " - also used by an ACL/map" is useless.
MINOR: session: don't always assume there's a listener

For outgoing connections initiated from an applet, there might not be
any listener. It's the case with peers, which resort to a hack consisting
in making the session's listener point to the peer. This listener is only
used for statistics now so it's much easier to check for its presence now.
MINOR: pattern: Add function to prune and reload pattern list.

This function it is used for dynamically update all the patterns
attached to one file. This function is atomic. All parsing or indexation
failures are reported in the haproxy logs.