PickledDB is now the default storage backend

🚀 Features

• Add plot commandline plot @gyom (#593)

🏗️ Enhancements

• Add where parameter to Storage.fetch_trials @breuleux (#584)
• Make command orion db setup ask for right arguments based on storage backend. @notoraptor (#586)
• Change the default database to PickledDB @abergeron (#585)
• Deterministic algorithm benchmark @donglinjy (#567)

🐛 Bug Fixes

• Add context-manager-enabled Trial subclass. @obilaniu (#587)
• Handle cases when trial.status is not reserved anymore locally. @bouthilx (#591)

🧰 Maintenance

• Ignore all test files in coverage @bouthilx (#592)
• Fix for coverage issue @abergeron (#581)
• Remove MongoDB dependency from core tests @breuleux (#582)
• Write generic tests for DB @satyaog (#590)