Resource throttling

[staheri14]

Problem
The store nodes are not able to throttle the resources they consume to provide storage service. At a minimum, users should be able to:

• The max upload and download bandwidth
• The maximum storage used
• the storage should follow the FIFO pattern
• The CPU usage

All these configurations will affect the consensus/synchronization layer #80.
For example, the storage and bandwidth constraints will affect the frequency and the number of messages that should be offloaded to the long-term storage layer (How long consensus nodes persist historical messages)