v0.17.0-rc.6

Bugfixing

• build: disable static linking and oniguruma
• rule: fix unability to check conditions of natural joins

Documentation

• docs: guide on how to optimize queries
• docs: add code example on how to manage serialized uast data
• docs: fix optional dependencies
• docs: Add instructions how to run in docker with bblfsh
• docs: improve uast functions documentation