Can't specify pod annotations

[brndnmtthws]

There's no way to add annotations to m3db pods at the moment. Specifically, I want to add these:

   annotations:
     prometheus.io/scrape: "true"
     prometheus.io/port: "7203"

Ideally it could be part of the cluster spec.

[schallert]

Sounds like a great idea! Happy to add this

[robskillington]

@brndnmtthws I added a PR for this, taken a bit to get to but here it is #155.

[brndnmtthws]

@brndnmtthws I added a PR for this, taken a bit to get to but here it is #155.

Sweet! I'm busy with other things, but I'll revisit m3db later.

[robskillington]

Closed with #155