Statefulset part M/S - create initcontainers

initcontainers should be used to :
1. initialize MariaDB configuration files (for each server set server-id.cnf and copy the predefined scripts to primary/secondary),
2. initialize MariaDB datadir, create root account, etc?
3. clone-mariadb (check unique name of a server and if is replica/secondary, clone data from previous server (1.replica will get data from primary, all other will get from previous peer).