Test 5.6.1 first candidate in all configuraions

Take https://cspkg.s3.amazonaws.com/index.html?prefix=custom/2469/amd64/
This is supposed to be 10.5.10-7 + 5.6.1 as in current develop-5 (created on my request Roman Navrotsky).

Follow installation and upgrade published instructions. Make sure the following permutations all work - once for fresh install and once for upgrade from 5.5.2:

1. Single node hard disks
1a. Single node S3
2. Three nodes hard disks (no shared storage) with MaxScale
3. Three nodes S3 shared storage and MaxScale
3a. Test failover

Set it up so that this can be repeated aouple more times as we get close to the final release candidate any day now.