Add interest groups to the member dashboard as it's own section

As requested by @scorbett in eclipse.org#727 (closed), we should look at updating the portal to indicate what interest groups a member is a part of if any. Additionally, we should consider giving them a list of available IGs to join as we do for projects and working groups.

@jharrisj1m any thoughts about adding this to the portal page? Just want to check in before we engage with the design team to get a new UI/UX mockup for the updated sections.