fix: Improve the configuration files handling

[Byloth]

Right now, you can configure CMaNGOS Docker by adding only the lines that differ from the default configuration values.
Sometimes, this behaviour can be confusing for users and - additionally - not having the complete list of all the available configuration options may lead to issues.

Editing the configuration should be a flawless experience without any sharp edges.

• Users must have access to a complete list of all the available configuration options.
• The replacement script must include safety checks for potentially outdated configuration entries that no longer exist in the default configuration.
• Both the configuration file and the replacement script must be compatible with [<section>] blocks.
  At the moment, this may cause some issues.