Remove generate-pixel and inter-shard-memory features, restrict more CPU functions

[shanemadden]

CPU functions and data related to using CPU unlocks are missing on private servers, and attempting to use the interfaces will cause a panic - they should be behind a feature.

Instead of adding one or two more granular sub-features of mmo, it seemed better to just consolidate generate-pixel and inter-shard-memory down into the mmo feature. If a practical case arises where a private server supports some of the mmo-like interfaces but not all of 'em, it might make sense to re-add that level of granularity, but for now it seems like overkill.

[scottbot95]

Might be worth also adding #[cfg(not(feature="sim"))] to the CPU halt functions Game.cpu.halt() does not exist in the sim.

[tiennou]

Might be worth also adding #[cfg(not(feature="sim"))] to the CPU halt functions Game.cpu.halt() does not exist in the sim.

There's a few more. I have Game.map, Game.market and PathFinder.CostMatrix also disabled in the profiler's default list there.

[shanemadden]

Good point on the stuff that's not in sim - I'll make an issue to track getting those added as well!