Consider removing caddy as part of the default installation setup/instructions

[pavish]

Problem

• Caddy is a reverse proxy which we provide in our docker-compose script and also instruct the user to use in the install from scratch setup.
• Most cloud platforms come with a reverse proxy service and chances are, if Mathesar is installed locally in a company's private network, they may not even need a reverse proxy.
• Making Caddy mandatory ends up in us having to instruct the user to configure it correctly, and debug issues from misconfiguration if any arise.
• Using a reverse proxy (Caddy/nginx) should be a user decision.

Suggestion

• Remove dependency on Caddy for installation purposes.
• Provide instructions for Production setup and out-of-the-box docker-compose scripts for Caddy & nginx, but do not make these scripts the default way to install.
• Default installation script/instructions should only focus on the Mathesar application.