Remove ANYONE_CAN_WRITE

The flag for ANYONE_CAN_WRITE is currently tracked in the configuration file deployed to each node. If an admin were to change this flag on a single node, bad things would happen.

It is preferable to have this option set on a network-wide basis using the config ledger.

UPD: The new Multi-signature approach doesn't require this flag at all.

Acceptance criteria:

• Either remove this flag from code (most likely) or move it to config ledger if it's really needed