CEP: Standardize Lock File Format

To facilitate cross tool compatibility (e.g. conda, mamba, and pixi), we should standardize a lock file format so that all tools are able to read and write the same lock files.

Currently, there are two options:

- conda-lock
- rattler-lock

The latter lock file type has seen more recent development, and made several improvements over what was initially developed by conda-lock; therefore, it would make a better choice to use as the model for standardization.

The CEP to be written shall include a precise description of how the lock file is to be formatted and include a reference link to the current implementation in rattler-lock.