Updated command line tool

Create a new `fab` command line utility to replace the existing one. Feature list includes:

- [ ] Create separate build and system loggers
- [ ] Allow build and system levels to be set independently
- [ ] Add `--quiet` mode to suppress almost all output
- [ ] Add `--detailed` mode to show commands being executed
- [ ] Log everything to a file in the project directory
- [ ] Improved progress indicators with the optional [rich](https://github.com/Textualize/rich) library
- [ ] Add spinners to tasks of unknown duration
- [ ] Add progress bars to multiprocessing pools
- [ ] Use rich log handlers
- [ ] Use rich generalised exception handling
- [ ] Support build targets, assuming they are defined in the build recipe
- [ ] Support `--fresh` option to remove an existing workspace
- [ ] Support `-DFOO=BAR` style command line options
- [ ] Unrecognised options should be passed through to the build recipe
- [ ] Support for getting help from from the build recipe argument parser, if any
- [ ] Basic recipe classes including:
- [ ] A base class which sets up infrastructure for other recipes
- [ ] A zero config recipe derived from the base class
- [ ] LFRic-Baf support