This PR updates the Docker installation and configuration instructions for LibreChat to improve clarity and readability. The changes include restructuring the document and refining certain parts for smoother understanding. Here's a summary of the modifications:

• The installation and configuration steps have been reorganized into separate sections for better organization.
• The LibreChat configuration section provides clearer instructions for updating the credentials in the docker-compose.yml file and setting up the .env file.

Type of change

Please delete options that are not relevant.

• Documentation update

How Has This Been Tested?

You can see it at https://github.com/ywkim/LibreChat/blob/docs-improve-docker-install/docs/install/docker_install.md

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules