DRAFT: i2p.i2p.2.4.0 segmented netdb static lifecycle

This alters the implementation of the sub-netDbs to always use the primary session hash of the client as the dbid, regardless of which dest and/or key is part of the communication. It creates the sub-db as soon as the ClientConnectionRunner is available. It separates the create/get methods and adds remove methods to the FNDS/SNDF.

It is not ready yet. Probably needs another day of work. Closes: #406 (closed)