* add 'map' cli command
- provides the following map information functions:
- list all available maps in the global registry
- display map metadata
- update docs with map command examples
* add list and info subcommands to map cli command
* rename map command list and info factory functions
* add --all flag to map info subcommand
* handle cmd.Help error
* remove squad support and switch to using pipelines only in RulesBuilder
* remove spawn_food.standard from legacy ruleset definitions
* bugfix: Royale map generates Standard food
* add maps support to CLI
* add automated tests for all registered GameMap implementations
* update README
- Update usage section in the README with the latest flags.
- Update default sample output (BoardState fields have changed,
OutOfBounds has been removed).
- Add section describing options for getting JSON output with the
`--output` and `--debug-requests` flag.
