Statistics tracking the same value but differing in storage type should be removed

[haykam821]

NucleoidMC/nucleoid-backend#18 adds aggregation for statistics on the backend, making storage types unnecessary. As such, the following statistics should be removed:

• One of plasmid:games_played, plasmid:games_won, and plasmid:games_lost, as the third value can be calculated from the other two if needed
• plasmid:quickest_time and plasmid:longest_time with a single plasmid:time