Add badge preview to Members page

[rrrutledge]

• The "preview" image for the Members page (https://innersourcecommons.org/members) should be the attached image.

• The image should also appear on the page. Here is where the badge should appear on the page:

Once we have this in place, we can use the members page to implement the "member" badge.

[spier]

@rrrutledge the correct URL for the member is this one, isn't it?
https://innersourcecommons.org/about/members/

Also when you say "preview image", do you mean the image that is shown e.g. when an URL is shared in slack?

If that's what you meant, I don't think that InnerSourceCommons/innersourcecommons.org#982 is implementing this correctly right now. Will leave a comment on that PR as well.