Inline processes that are used only once.

As a happy side effect, delete processes that are never used.
Split LOTOS.Synthesize to LOTOS.Synthesize.AST.

This reduces re-compile time by only forcing the new AST module to
rebuild if LOTOS.AST changes. Since the AST modules use Template
Haskell to generate RepLib typeclass instances, they're rather slow to
compile.