To avoid duplicate source code, the original haproxy function is used to
generate the OpenTracing runtime context UUID.
Also, the structure flt_ot_runtime_context is simplified because the
detailed definition of UUID is removed from it (struct flt_ot_uuid),
ie the UUID is left only in the form of a string.
This one is the last optional module to build with haproxy, so let's move
it to addons/. It was renamed to "ot" as it was the only one whose USE_*
option did not match the directory name, now this is consistent.
Few changes were required, only the Makefile, and doc were adjusted, as
the directory was already self-contained and relocatable.
Miroslav Zagorac
Willy Tarreau