This diff fixes RPC commands that were broken in two ways.
The alias resolving code was moved from the Contacts class to the alias module in D14547. This broke bunch of RPC commands to used `wallet.contacts.resolve`.
Note that nothing in the moved code was specific to a particular wallet. It is just code to validate an address or convert an alias to an address.
The broadcast, deserialize and signtransaction commands were broken because the `Transaction` class now expect bytes in `__init__`. It was tested using the command line in D14530, but not with a RPC call. Call `rawtx_from_str` directly in the 3 commands instead of making it a type conversion in argparse, so that it works both as a command line command and an RPC command.