Command line dispatcher. Given a command line call to `brainglobe`
it calls the correct function, depending on which `command` was
command: str. Name of the command:
- list: list available atlases
- install: isntall new atlas
- update: update an installed atlas
show: bool. If True when using `list` shows the local path of
and when using 'config' it prints the modify config results.
atlas_name: ts. Used with `update` and `install`, name of the atlas to
force: bool, used with `update`. If True it forces the update