Started the work on the release notes for release 1.8
Started the work on the release notes for release 1.8


Former-commit-id: 1c6e3cb5e5c4c52a70fae6f0ce78c8c0140e2e5a
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine