This change makes ReconcileOptions fully reusable by:

1. Replacing ResourceBuilder with a Visitor that can be generically
plugged in.  This decouples the use of file input from the options.
2. Replacing core client with namespace client since that smaller
interface is what is needed by RunReconcile.
3. All fields are now checked by Validate as a way to document that
they should be set before calling RunReconcile.
Signed-off-by: Monis Khan <mkhan@redhat.com>