MaybeSDK

The "Maybe" SDK functions somewhat differently from ListSDK or others, because Maybe is not handled as a specific RTValue but through the general RTConstructor type. This is because it is treated as such in the IR - Maybe values are initialized with constructors and pattern matched as such.

TODO: This distinction should be refactored away. This entails:

• Adding RTValue variants for Maybe (and Result, while we're at it)
• Adding all supporting code for such (coercers + anything else)
• Adding special cases to the Apply handling for Constructors, to create these special RTValues instead of the general form
• Adding special cases to Constructor pattern matching to recognize these forms
• Changing the RTValue to MDM process to reflect the new form
• In this file:
• Remove toOption and toMaybe
• Change the types from RT.ConstructorResult to RT.Maybe
• Change toOption(arg) calls to arg.value and toMaybe(result) calls to RT.Maybe(result)