add deployment scripts

[maany]

Description

• add a script to generate .env file
• add a test to validate the .env file

Motivation

The containers repo for webui should not contain templates and external scripts that decide how a given version of webui should be configured. It should be handled internally by the webui itself

Change

• use liquid templates for the .env file
• generate .env file from environment variables
• write a jest test to validate the generated .env file

Additional Information

• [ ] It is related to the Storybook?
• [ ] It is related to the GitHub Actions?
• [X] It is related to the developer tools?