Skip proof-of-work for local and organisation messages

[jaytaph]

If a message is located on the same server, we could skip the proof-of-work (configurable)

If a message is send to somebody from the same organisation, we could skip the proof-of-work (configurable)

[jaytaph]

Proposal:

• add configuration setting for local delivery without proof-of-work (same routing ID)
• check if we can do the same for organisations (the header might not have org info)