Context

This PR

1. Fixes .devcontainer in coder/coder doesn't create a working dev environment.  #7591
2. Fixes dogfood: use same/similar environment for .devcontainer and dogfood template. #5211

Contributes to #7676

What does it do

• Use the devcontainer feature to enable docker-in-docker.
• Use the codercom/oss-dogfood:latest image that we push on every change to Dockerfile
  

  coder/.github/workflows/dogfood.yaml

  Line 45 in 59246e0

  - name: Build and push

Testing

I have tested the proposed modification in .devcontainer.
with

• VM with Docker installed
• GitHub Codespaces (requires --privileged)

with following commands

1. make fmt
2. make lint
3. make test
4. ./scripts/develop.sh

   For GitHub Codespaces, set export NODE_OPTIONS=--max-old-space-size=4096 instead of 8196 as the max memory provided by a 4 core 8 GB workspace is 7139 Mb

What we can do Next

Next, I am going to test a dogfood template using coder/envbuilder and .devcontainer

I guess we can also safely remove the docker installation from our dogfood Dockerfile

Also, I would like to remove most of the packages we install in Dockerfile to be replaced with devcontainer features,
e.g.,

1. go
2. node
3. rust (if we need this)
4. Postgres
5. GitHub CLI
6. Hugo
7. etc...

This will make it modular and easy to maintain.