Implement storage of state metadata

[Alex Yurchenko]

Following discussion in https://bugs.launchpad.net/codership-mysql/+bug/411814

Currently application does not save its state wsrep metadata (state UUID and sequence number) at all. It should do it, preferably within the data, to simplify manageability (like presence of these metadata in mysqldump) and reduce risk of errors.

Currently Galera wsrep provider can store the metadata, but this only a workaround and not a long term solution, as it is wsrep implementation-specific (there is no contract about it in the wsrep API) and it is stored separately from the state (https://bugs.launchpad.net/codership-mysql/+bug/378216).