Engine Atmos Control Console

This PR expands on the fix from 9fea39dea216ed6fa1f1aa167d5c16c582a5e9ee.

* Atmos control computers can set the air injector flow rate.
* The SM engine gets it's own atmos control computer type that sets external pressure bounds instead of internal, as appropriate for the engine core which is not an air storage tank. Players now have direct control over the minimum engine core pressure, properly preventing the engine pump imbalance bug that was corrected by 9fea39dea216ed6fa1f1aa167d5c16c582a5e9ee.
* New high-power engine vent pump type whose max flow rate matches the air injector max flow rate.

Note: The "toggle power" command on atmos control computers appears to be broken, and I couldn't figure out why. It's probably not something I'm going to fix in this PR though.