doc: add historical 0.19.0 release notes
doc: add historical 0.19.0 release notes

Former-commit-id: 4859188030c7f9c15e859e57f371a49fc966b10d
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin