Node status and synchronization doc

[nyeates]

How do we know node is synced up and working on blockchain?

Didnt make it in the long masternode guide, because it is getting long, and because this topic can be self sustaining and used by other audiences (nodes).

[nyeates]

FIXME: I need to remember to link to this document from the masternode guide.

[phamvancam2104]

I love this proposal @nyeates. Let me have a look at it.