Co-authored-by: Anatol Lupacescu <anatollupacescu@gmail.com>
Co-authored-by: Ralph Pichler <pichler.ralph@gmail.com>

add forwarder reattempt behaviour on overdrafts

This PR adds postage stamp indexing to enforce overissuance 
on the storer node side. This allows for slot overriding and reusage.
It also adds immutable stamps functionality. 
Co-authored-by: Esad Akar <esadakar@gmail.com>

Speeds up the topology build by dividing the connect neighbor
method into two separate phases executed in sequential order.
The first phase makes a number of concurrent connections not
bigger than what is considered for the bin to be saturated. The
second phase takes care of the rest of the connection in a
regular manner.

Adds the following metrics:

- number of currently connected peers
- number of currently disconnected peers
- total number of kicked out peers