Migrate university to use lfs for images

.gitattributes

...university/high-availability/aws/img/auto-scaling-det.png

doc/university/high-availability/aws/img/db-subnet-group.png

doc/university/high-availability/aws/img/ec-subnet.png

...versity/high-availability/aws/img/elastic-file-system.png

doc/university/high-availability/aws/img/ig-rt.png

doc/university/high-availability/aws/img/ig.png

doc/university/high-availability/aws/img/instance_specs.png

doc/university/high-availability/aws/img/new_vpc.png

doc/university/high-availability/aws/img/policies.png

doc/university/high-availability/aws/img/rds-net-opt.png

doc/university/high-availability/aws/img/rds-sec-group.png

...niversity/high-availability/aws/img/redis-cluster-det.png

doc/university/high-availability/aws/img/redis-net.png

doc/university/high-availability/aws/img/route_table.png

doc/university/high-availability/aws/img/subnet.png