clients: add weston-debug

A tool for accessing the zcompositor_debug_v1 interface features.

Installed along weston-info, because it should be potentially useful for
people running libweston-based compositors.

Signed-off-by: Pekka Paalanen <pq@iki.fi>

Added a man page for weston-debug client

Signed-off-by: Maniraj Devadoss <Maniraj.Devadoss@in.bosch.com>
[Pekka: fixed 'missing braces aroudn initializer' warning]

Add --list and --all arguments, using interface advertisement.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Emre Ucan <eucan@de.adit-jv.com>