Substrait Governance Proposal

[Jacques Nadeau]

Hey All, 

I've started a document attempting to outline the Substrait governance model. As we've discussed previously in the project, the goal here is "Apache-ish" with some alterations. 

The document can be found here: 

https://bit.ly/3DyKAxg

The document is open for comments. Please ping me directly if you'd like to have edit access (please use suggest changes). I'm avoiding opening changes to the world due to spam concerns.

It's a skeleton of what we need to cover but it would be great getting help filling this out and finalizing it.