Add a way to tell what role repmgr thinks we are

[DAlperin]

I stole this sql from repmgrs internals https://github.com/EnterpriseDB/repmgr/blob/3b897318998114ba2760057c9a18bc7601771ca3/dbutils.c#L2773.

I need a some sort of chaos monkey script to test this kind of code.

[davissp14]

👍

[DAlperin]

@davissp14 tested this, works as expected now. Ready to merge if you are

[DAlperin]

Actually no, this isn't quite there yet. We end up in the:

// If we are here, we are a standby or a demoted primary who needs
// to be reconfigured as a standby.

Also if we are joining the cluster for the first time when there already is an elected leader. In that case we don't have a role at all yet. I need to handle that.

[DAlperin]

Ok fixed.