Simplify handling of server_config.json #1576

After the completion of #1206, the server_config.json no longer needs to be copied to a writable location. Both the code and some manual setup procedures can be simplified if Monkey Island behaves as follows.

1. If cc/monkey_island/server_config.json exists, read it and .override the default configuration values with values in this file (docker only).
2. If the user provided the --server-config option on the command line, read the user-provided server_config.json and override any default values with the user-provided values.

This removes the circular dependency between the server_config.json and the data_dir option. It also means that a user-provided server_config.json only needs to provide settings that deviate from the default.

Tasks

• Remove logic that copies server_config.json to data_dir (0d) - @VakarisZ
• Modify the code in config_setup.py load defaults if cc/monkey_island/server_config.json does not exist, or load it if it does. (0d) - @VakarisZ
• Update server_config.json for each package to include only settings that deviate from defaults. (0d) @VakarisZ
  • Docker
• If the user provided a custom server_config.json with the --server-config option, update the IslandConfigOptions object with the values from the user-provided file. (0.5d) @VakarisZ
• Simplify/correct/improve any instructions in the documentation that refer to the server_config.json. (0d)
  • https://www.guardicore.com/infectionmonkey/docs/reference/data_directory/
  • Add FAQ about log level
  • Certificate setup:
    • AppImage
    • Docker
    • MSI
• Test all packages manually (0d)
  • AppImage
  • Docker
  • MSI