Add the infrastructure monitoring graphs to the admin menu

[equivalentideas]

The graphs @auxesis has set up are really helpful in seeing what's wrong with morph.io and making sure your fix works. We share make it an easy link from the admin menu, rather than having to remember the link.

Also in chat, @auxesis suggests:

@equivalentideas if you want to make it more official, set up a CNAME for graphs.morph.io to point to morph-monitor-production-1698444042.us-west-2.elb.amazonaws.com.

then we can just link to graphs.morph.io from the admin interface (edited)

[henare]

http://graphs.morph.io/ is now in place.