Instead of downloading it from the github repo on every build (in
`base.dockerfile`), we vendor the supervisor extension so we can look to
fix the buffer overflow problem in supervisor logs.
After this is merged, after a day/two, we'll be removing `git`,
`python3-pip` and the supervisor-stdout extension from
`base.dockerfile`.
This is part of supporting running Appsmith with readonly root FS. This
moves the supervisord configuration, and runtime files, like the unix
socket file, and the PID file, to `$TMP`.
Move the files that are copied into the Docker image, into an `fs`
folder, that reflects the folder structure of that in the image. This
means two things right away:
1. A single `COPY` instruction in `Dockerfile` is enough to copy all the
files to their places.
2. The structure of files in the repo reflects that in the Docker image.
This makes working with the files/folders and troubleshooting with them
much easier.
❗ Note: **There's actually only 3 files changed, rest are just moved.**
