This does 3 things:
- Add a NoPin option to the adder. When set to true, the adding process does not
send a pin in the end.
- When user-allocations are set and local=true happens, we do not overwrite
the allocations returned by the allocator to include the local peer
anymore, as this could alter user-allocations.
- Some code improvement (remove pointers).
Local dagservice is not really a local as it add to other peers as well.
It is a dagservice that does not perform sharding. Since we are going to
have a local dagservice(one that adds only to the local peer), renaming
this `single` dagservice
