Use dataclasses to reduce the complexity of the config and environment packages

[dvaccarosenna]

Several classes in lmctl.config and lmctl.environment are just data objects for configuration, parsed from a YAML file. A lot of code has been written to parse the YAML content, to a dictionary, then the final classes.

These packages may be greatly simplified by using dataclasses. This could be either native Python dataclasses or by using a validation library such as Pydantic.

By doing so, changes and maintenance of these packages would be greatly reduced as additional parsing logic would not be required each time there is a change (e.g. for future Zen auth support and Site Planner support).