Add page that describes membership levels in no uncertain terms.

[starbelly]

Currently, it's not clear what the membership levels are to some people. I've spoken with a few people and they were not aware of what membership is, whether it costs money, etc. The join us link on the site does indeed explain that, but perhaps we need a page on the site itself that outlines this in a familiar way (e.g, https://getbootstrap.com/docs/4.0/examples/pricing/)

[benoitc]

should be moved to website, and adressed to sponsorship group imo.

[benoitc]

someone from the sponsoring group should help us on that. contacted on their slack.

[starbelly]

@benoitc Yes, I agree.