[UI] Mouse controls for health-related values on character sheet

Now left/right click support for the Max health values has been added to add/remove bonuses, it would a good to add mouse support across the board to the numeric values on the sidebar (for starters, there may be other candidates later).

The following should be standardised for consistency.

• Left Click - Increment Value
• Right Click - Decrement Value
• Mouse Wheel - Increment/Decrement Value
• Doubleclick - Reset

The Reset function would change depending on context, as follows:

• Max Vigor/Resolve (reset to default calculated maximum with no bonuses applied)
• Current Vigor/Resolve (reset to current Max Vigor)
• Fatigue/Despair (reset to zero)