Move RGB composites to .yaml files

[CameronLP]

The RGB composites can be be defined in a configuration file, avoid the need to generate them manual: https://satpy.readthedocs.io/en/stable/composites.html

[CameronLP]

Relevant documentation: https://satpy.readthedocs.io/en/stable/composites.html#creating-composite-configuration-files

[CameronLP]

Add the RGB composite definition file hypso1.yaml in the composites directory. Files in this directory are automatically loaded if they the composites directory is part of the $SATPY_CONFIG_PATH/composites/ path.