Easier creation of batch specs

Created by: chrispine

Based on presentations by @LawnGnome, @courier-new, @adeola-ak, and our design sprint with @danielmarquespt at our Lisbon offsite. Lots of cool ideas here:

• Notebooks as a way to ease into BC
• Build-a-BatchSpec
• Tutorial/sandbox ("AdeolaHub")

For more context, see our offsite notes