Add non-root dev container user (home-assistant#34984)

* add non-root container user

* fix dockerfile and homeassistant editable install

* just install in home directory

* less impactful default changes

* separate RUN for better layer caching

* use vscode-remote base image

Dockerfile.dev

@@ -1,4 +1,4 @@
-FROM python:3.8
+FROM mcr.microsoft.com/vscode/devcontainers/python:0-3.8
 
 RUN \
     apt-get update && apt-get install -y --no-install-recommends \