doc: remove outdated doc that must be updated with datastore
doc: remove outdated doc that must be updated with datastore

Former-commit-id: b5c9ec85e6539af9eb7bc3d36e409e9eff7d056a [formerly b5c9ec85e6539af9eb7bc3d36e409e9eff7d056a [formerly cd767b25d3f23b7fd27e85b84532233d3d41bcf5]]
Former-commit-id: fc1ef1d02e819c972f4343d05eb34671c74c593c
Former-commit-id: cd50d36f889eae121643249d63b9f2628bda03b7
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine