Allow for Chords in the EnhancedInputUserSettings

Licensees and end users would like to be able to allow their players to remap a single action to something that has a chord. For example, remapping an action whose default key is "X" , and allowing the player to remap to "Shift + X" to trigger it.

We would have to approach this by somehow automatically adding a Chord Input Trigger to the input action during Rebuild Control Mappings in the Enhanced Input subsystem interface. The key profile already has a "GetPlayerMappedKeysForRebuildControlMappings" function, so maybe instead of having an out param of just FKeys, we can have an aout array of some struct that stores the key you want, plus an an array of modifiers or something.