When running with a custom `PORT` env variable, NGINX server will be
listening on this port. In the backend's startup script, `run-java.sh`,
we're checking for RTS being up or not, at `localhost`. So when the port
is not 80, then this will never succeed, because it'll be looking for
NGINX at the wrong port.
Instead, the fix here will make the backend startup script hit RTS
_directly_ on RTS server's own port, instead of going via NGINX. This
means it's independent of both the `PORT` env variable and the NGINX
server, and only dependent on RTS being up, which is really what we want
here.
When PostgreSQL starts, we see the following errors in the logs:
```
mkdir:
cannot create directory ‘/tmp/appsmith/postgres-stats’
: Permission denied
```
And then this over and over again:
```
postgres stdout | 2023-09-19 15:34:34.504 UTC [1759] LOG: could not open temporary statistics file "/tmp/appsmith/postgres-stats/global.tmp": No such file or directory
```
The problem is that in `postgres.conf`, we set `user=postgres`, which
doesn't have access to create things in `/tmp`.
This PR removes this configuration and lets the default be, which will
be a temp folders _under_ the data directory.
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`.
This is another step towards supporting running with readonly root FS,
and only making runtime changes in the container in `/tmp` or in
`/appsmith-stacks`, and nowhere else.
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.**
