This patch ads proxysql-config role
which is used for generating users and
rules configuration.

Change-Id: I1fcb0e8040ea55f8f6b8384a56479eabdaf61c33

This patch adds loadbalancer-config role
which is "wrapper" around haproxy-config
and proxysql-config role which will be added
in follow-up patches.

Change-Id: I64d41507317081e1860a94b9481a85c8d400797d