compiler: Refactor Compiler To Remove Ambiguities

There were significant overlaps in the names of data structures
between the compiler and the language that made it necessary
to litter the code with P4Lang.xxxx. This refactor removes that
requirement in most places (Parser is ambiguous wherever TreeSitter
is used -- cannot avoid that!)

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

Sources/Cli/main.swift

@@ -94,7 +94,7 @@ extension Cli {
         return
       }
 
-      let maybe_program = Program.Compile(source.getSource())
+      let maybe_program = SpecialCompilers.ProgramCompiler.Compile(source.getSource())
       guard case .Ok(_) = maybe_program else {
         let feedback = CompilationFeedback(source, [maybe_program.error()!], formatter)
         print(feedback.feedback)
@@ -134,7 +134,7 @@ extension Cli {
         return
       }
 
-      let maybe_program = Program.Compile(source.getSource())
+      let maybe_program = SpecialCompilers.ProgramCompiler.Compile(source.getSource())
       guard case .Ok(let program) = maybe_program else {
         print(ErrorWithLabel("Compiler Error", maybe_source.error()!).format(formatter))
         return