doc: Add historical release notes for 0.18.1
doc: Add historical release notes for 0.18.1

Former-commit-id: 9aa8be256ce8a3a2bf8cd52ded4c39e78d7fee8d
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin