fix(metadata): change RecordingMetadataManager startup process

[maxcao13]

Fixes #1085

[andrewazores]

Nice, pretty compact change but this already ensures that migration doesn't happen until after discovery startup is completed, and also should push the migration work off onto a verticle worker thread.

Do you intend to also implement the lazy evaluation stuff we talked about previously or do you think this change is already sufficient?

[maxcao13]

Nice, pretty compact change but this already ensures that migration doesn't happen until after discovery startup is completed, and also should push the migration work off onto a verticle worker thread.

Do you intend to also implement the lazy evaluation stuff we talked about previously or do you think this change is already sufficient?

I think it's sufficient enough. As it is right now, I think the notifications that come in which the Manager hooks into already sort of allows it to do lazy evaluation along with the eager startup metadata pruning, so in fact maybe there is no need to do startup pruning at all but I guess it doesn't hurt to have redundancy in case notifications aren't seen correctly somehow.