change to Docker entrypoint.sh

Hi All!

I am new to this, so I apologize beforehand if it's not entirely kosher,
but I have a proposed change to the Dockerfile entrypoint.sh to allow for
configurable servers.json filename path.

The reasoning behind this is that I have a Kubernetes deployment of pgadmin
where I build a ConfigMap sort of dynamically. I can make the file appear
in /pgadmin4, but it removes the contents of the directory for me
(helpful!). Instead, I put it into a separate directory and set a new
environment variable that defaults to the old pathname
(backwards-compatible!) but allows me to set a custom environment variable
in my custom Helm chart for my deployment.

The code is here:
https://github.com/penguincoder/pgadmin4/commit/0865400385ac0d03bf69d183e8cd9aaec6dcf318

Is this something that anyone is interested in?
Does it meet your coding standards?
What do I do next?

I would love to move back to the "official" pgadmin container.

Thanks for your time,

Andrew