compiler, runtime: Begin Runtime Refactor

Ultimately, the goal is to completely separate the compilation from
the runtime to make it possible to have the interpreter/evaluator
be "just another" entity that can perform meaningful work when
given a parsed GP4 program.

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

Sources/P4Runtime/Control.swift

@@ -91,10 +91,14 @@ extension Control: LibraryCallable {
   }
 }
 
-extension Action: EvaluatableStatement {
+extension Action: P4Statement {
+  public func effect(context: Common.CompilerContext) -> Common.CompilerContext {
+    return context
+  }
+
   public func evaluate(
     execution: Common.ProgramExecution
-  ) -> (Common.ControlFlow, Common.ProgramExecution) {
+  ) -> (ControlFlow, Common.ProgramExecution) {
     if let body = self.body {
       return body.evaluate(execution: execution)
     }