bump to 3.7.4.1

* update base from code-server 3.4.1 to 3.7.4
* clean up apt cache after install
* install golang using update-golangh
* add kubectl
* add kubens & kubectx

add basic readme

Add pip & virtualenvwrapper; bump to v1.939.2

Give `coder` user access to docker socket; 1.939.1

Add code-server-tools Dockerfile

code-server-tools add some basic tools to the
codercom/code-server docker image.