Add RatePack limits

[dnwiebe]

1. Let user establish price limits beyond which he will not pay.
2. Make these limits part of the Gossip, so that other Nodes will be able to use that information to set their own RatePacks.
3. Keep in mind that this is a Gossip modification that will require migration.

[kauri-hero]

by this time, we want to expect that a matured UI interface will be able to inspect what the "patch" average costing is, and be able to present to the user so "they know" what an average would be in the neighborhood at the time.

[kauri-hero]

@bertllll - nice to have a way to start up Neighborhood connection where user can start up and "not have rate packs establish" (or preliminary rates) and have the rate Packs set to an average in line with the neighborhood.