Restore: PostgreSQL

[plirglo]

Postgresql recovery includes:

Database data and metadata dump using pg_dumpall

If multinode configuration is used, and failover action has changed database cluster status (one node down, switchover) it's still possible to create backup. But before database restore, cluster needs to be recovered by running epicli apply and next epicli recovery to restore database data. By default we don't support recovery database configuration from backup since this needs to be done using epicli apply or manually by copying backed up files accordingly to cluster state. The reason of this is that is very risky to restore configuration files among different database cluster configurations.

https://github.com/epiphany-platform/epiphany/blob/develop/docs/home/howto/BACKUP.md

PR #1359

[jetalone85]

@plirglo tested restore scenario: single node PostgreSQL, 2 nodes PostgreSQL done, works for me

[jetalone85]

Tested restore scenario: single node PostgreSQL, clustered nodes PostgreSQL; on Ubuntu and RedHat.