Move most of the BuildConfiguration specific functions

Note: I didn't fix all the connects and there are a few missing things.
This compiles, more work is coming.

src/plugins/genericprojectmanager/genericbuildconfiguration.h

@@ -44,6 +44,9 @@ class GenericBuildConfiguration : public ProjectExplorer::BuildConfiguration
 public:
     GenericBuildConfiguration(GenericProject *pro);
     GenericBuildConfiguration(GenericBuildConfiguration *source);
+
+    virtual ProjectExplorer::Environment environment() const;
+    virtual QString buildDirectory() const;
 };
 
 } // namespace GenericProjectManager