[CDF-23856] 🚶 Pydantic Group (#1560)

# Description
Toolkit: CLI for managing CDF configuration as code. The CDF resources
are configured in YAML files that are typically checked into version
control.

Context: Up until now we have used the `cognite-sdk` data classes when
loading these YAML files. This gives poor error messages. In addition,
Toolkit has a few deviation from the API spec, the most common Toolkit
always uses external IDs instead of internal IDs. We have made the
decision to implement `pydantic` to be able to give better error
messages to the user when they mistype their `YAML` files.

Reason for size of this PR: Our Groups API has a lot of capabilities.

## Changelog

- [x] Patch
- [ ] Minor
- [ ] Skip

## cdf

### Improved

- Improved error message if group is not following the API
specifications.

## templates

No changes.
