bitcoin-wallet tool: Drop libbitcoin_server.a dependency
bitcoin-wallet tool: Drop libbitcoin_server.a dependency

This ensures wallet code doesn't access node global state, avoiding bugs like
https://github.com/bitcoin/bitcoin/pull/15557#discussion_r267735431

DigitalPandacoin/pandacoin,peercoin/peercoin,peercoin/peercoin,DigitalPandacoin/pandacoin,peercoin/peercoin,peercoin/peercoin,peercoin/peercoin,peercoin/peercoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin