Break apart Plutarch.Bool

[kozross]

This does several things:

• PSBool is now in Plutarch.LedgerApi.Utils, as it's not used anywhere else
• PBool is now housed in Plutarch.Builtin.Bool, along with its major functionality
• A new binding for the sole boolean builtin (with the right type) exists
• PEq now resides in its own module
• PPartialOrd and POrd now reside in their own modules
• pif' is now exported from the Prelude