Connect apiserver to load balancer

[pbiggar]

Note: most of this is deployed already.

This is most of what's required to get a canvas loading.

Connect apiserver to load balancer:

• add ingress rules to send darklang.com/a/trydarkfsharp to apiserver

Move apiserver back to the default namespace

• I moved apiserver to the darklang namespace to have tighter firewall rules
• Unfortunately, the GCE ingress doesn't all ExternalNames which means we can't connect an ingress in the default namespace to a service in the darklang namespace
• so now I've moved it back

Configure GCE load balancer for apiserver:

• added backendconfig for apiserver-service (this is used to configure the health check)
• tried a few things, but eventually settled on allowing the GCE healthcheck to use /k8s/livenessProbe on apiserver, coming in via nginx
• added kubeconform and some definition for our cluster's CRD - this allows linting of backendconfig
• refactor yamllinter to run in about a secondp

Updated the Dockerfile versions:

• new fantomas, prettier, shellchecker, yapf, honeytail,

Fixes some things needed to load the canvas UI:

• copied necessary files to apiserver production container
• fixed a bug in hashedFilename
• fixed significant bugs in validating username and canvasnames
• (not in this PR - fixed incorrect names in production DB)