Ability to set any patroni DCS options

[baznikin]

Only subset of patroni options are implemented in operator CRD. It would be great to allow user to specify any options, unsupported by operator. Just join some user specified overrides to final options. We need ignore_slots really hard (there is PR already #3021); in the future it's possible we'll want something else. Mark it clearly this overrides are unsupported, not validated and it is user's responsibility to set it up correctly.