Update database start/stop to handle multi-tier system replication

[arbulu89]

Description

Update database start/stop operations to handle multi-tier system replication setups.

3 tiers is the maximum number of tiers in a HANA system replication setup.

• The start process must be done starting from tier 1, followed by tier 2 and finally tier 3. We can have more than one database in tier 2 and 3 (multi target setup).
• The stop process must be done starting from tier 3, followed by tier 2 and finally tier 1. We can have more than one database in tier 2 and 3.
• If system replication is not configured, we just simply start/stop the unique db (it would mean, system replication tier is null).

At the end, it is just an improvement of the already existing operation, the current behaviour still being totally possible.

PD: Whole operation rollback process is not in-place. Wanda doesn't support this (yet, at least). In any case, as the process is sequential, for example, if some tier during a start process fails, well, the user still wanted to start them, so having a partial started system is not harmful.

How was this tested?

Manual testing

Did you update the documentation?

I guess we might need to update docs here. @abravosuse what do you think?

[coveralls]

coverage: 93.795%. remained the same
when pulling 7c8029b on database-multi-tier-start-stop
into c0ded39 on main.

[abravosuse]

I guess we might need to update docs here. @abravosuse what do you think?

@arbulu89 yes, we need to keep documentation about ops up to date.

[abravosuse]

Code apart, based on one-on-one discussions, it LGTM.