[upstream] Additions to Website
[upstream] Additions to Website

Added mentions and links to sessions for project onboarding and the
git and gerrit lunch and learn. Also separated these with the
mention of openstack academy to a 'Continued Education in Boston'
section to set them apart from the other Upstream Institute details.

Change-Id: I0d6828566857dd91fb3eeacab2302b62f43fc140

openstack/training-guides,openstack/training-guides