Issue Boards Landing Page

Landing page for Issue Boards.

TODO:

• Fill in remaining filler copy
• Add actual YouTube video
• Add actual screenshots
• Add actual links
• Add label "aside" image (or maybe make those actual HTML?)

Current page as of August 11:

If you want to check this out locally, see http://localhost:4567/issue-boards

cc: @AshleyS @axil @amara @virtuacreative @lukebabb