Create governance document

[ytsarev]

As part of CNCF onboarding at cncf/sandbox#251 we need to adopt https://github.com/opengovernance/opengovernance.dev

[ytsarev]

Interesting conversation on Open Governance topic https://www.tfir.io/open-source-open-governance-dirk-hohndel-swapnil-bhartiya/

[somaritane]

Fixed by cncf/toc#458