MicroCeph Remote Replication (1/3): Remote Awareness

[UtkarshBhatthere]

Description

This PR implements the "Making MicroCeph aware of remote cluster" segment of Remote Replication requirement.
It includes:

1. Cluster Export: Command/API to export ceph cluster state.
2. Remote Import: Command/API to import a remote MicroCeph cluster in MicroCeph.
3. Remote List: Command/API to list all remotes configured on the cluster.
4. Remotes Table: To persist localCluster-remoteCluster pair in Dqlite.
5. RBD-Mirror: Daemon enablement using service placement interface.
6. Tests

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• CleanCode (Code refactor, test updates, does not introduce functional changes)
• Documentation update (Doc only change)

How Has This Been Tested?

• Add CI tests

Contributor's Checklist

Please check that you have:

• self-reviewed the code in this PR.
• added code comments, particularly in hard-to-understand areas.
• updated the user documentation with corresponding changes.
• added tests to verify effectiveness of this change.

[sabaini]

Hey @UtkarshBhatthere thanks for the massive work. I've left some comments inline

[sabaini]

Heya @UtkarshBhatthere , thanks!
I've added some comments/requests for doc, also a question wrt to privileges

[sabaini]

Hey @UtkarshBhatthere this looks great. I've added one small testing improvement suggestion but otherwise +1

[lmlg]

LGTM, just a couple nits.

[lmlg]

lgtm, thanks for addressing the comments