improve Patroni config sync

[FxKu]

the current way of syncing and comparing Patroni config has a few issues:

1. returned Patroni config can be empty but not nil, e.g. during restore which can crash the operator
2. by default synchronous_mode and synchronous_mode_strict are not set in Spilo and create a diff with desired state even when not set, because the default is false
3. slot comparison does not work even when they are semantically the same because go types are different (map[string]map[string]string vs. map[string]interface{}). Moreover, the slot settings should not be compared as a whole. It should only be checked if specified slots exist and if they differ.

[Jan-M]

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[FxKu]

👍