Redback-surrogates

Changed
- Emulator trained on a denser array with some additional fixes

Changed
- Minor changes to the documentation/interface for afterglow emulator.

Added
- An emulator for the tophat_redback afterglow model

Changed
- Minor changes to the documentation.
- Code style changes to make it more consistent with redback.

Added
- Pypi installation
- Standardized logging
- Several new models
- Several examples
- Docs