MINOR: peers: add informative flags about resync process for debugging

MINOR: peers: add informative flags about resync process for debugging

This patch adds miscellenous informative flags raised during the initial
full resync process performed during the reload for debugging purpose.

0x00000010: Timeout waiting for a full resync from a local node
0x00000020: Timeout waiting for a full resync from a remote node
0x00000040: Session aborted learning from a local node
0x00000080: Session aborted learning from a remote node
0x00000100: A local node teach us and was fully up to date
0x00000200: A remote node teach us and was fully up to date
0x00000400: A local node teach us but was partially up to date
0x00000800: A remote node teach us but was partially up to date
0x00001000: A local node was assigned for a full resync
0x00002000: A remote node was assigned for a full resync
0x00004000: A resync was explicitly requested

This patch could be backported on any supported branch

(cherry picked from commit ccdfbae62cc5e5023bc857cbc04f680145435a1e)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>