LibWeb: Convert the Location object to IDL

This includes:

- Moving it from Bindings/ to HTML/
- Renaming it from LocationObject to Location
- Removing the manual definitions of the constructor and prototype
- Removing special handling of the Location interface from the bindings
  generator
- Converting the JS_DEFINE_NATIVE_FUNCTIONs to regular functions
  returning DeprecatedString instead of PrimitiveString
- Adding missing (no-op) setters for the various attributes, which are
  expected to exist by the bindings generator

Userland/Libraries/LibWeb/DOM/Document.idl

@@ -19,6 +19,7 @@
 #import <HTML/HTMLElement.idl>
 #import <HTML/HTMLHeadElement.idl>
 #import <HTML/HTMLScriptElement.idl>
+#import <HTML/Location.idl>
 #import <Selection/Selection.idl>
 
 // https://dom.spec.whatwg.org/#document
@@ -28,7 +29,6 @@ interface Document : Node {
 
     boolean hasFocus();
 
-    // FIXME: These attributes currently don't do anything.
     [PutForwards=href, LegacyUnforgeable] readonly attribute Location? location;
     attribute USVString domain;