Some new config options

[donkeyrat]

I found some important oversights in the mod's configurability, so I opted to make a pull request that adds them. The new config options are:

• splashThreshold: Allows tweaking at what velocity an entity creates a splash.
• spectralArrowTrails: Replaces improvedSpectralArrows, works just like the Allay trail configuration.
• freezeFrames: Allows changing how many frames parrying freezes the screen for.