config.json: modify topics & add difficulty for bowling (#754)
config.json: modify topics & add difficulty for bowling (#754)

Added "Algorithms" due to the complexity of the scoring algorithm,
changed topics ordering to alphabetical.

See #345 & #731
exercism/xgo,leenipper/xgo,leenipper/xgo,exercism/xgo,robphoenix/exercism-go,robphoenix/exercism-go