require a successful write request before concluding pushsync was attempted as a forwarder

On top of the current information, the returned data are
extended by: label, depth, amount, bucketDepth,
blockNumber, and immutableFlag.

This reverts commit e1025971.

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>