LibJS: Rename Environment Records so they match the spec :^)

This patch makes the following name changes:

- ScopeObject => EnvironmentRecord
- LexicalEnvironment => DeclarativeEnvironmentRecord
- WithScope => ObjectEnvironmentRecord

Userland/Libraries/LibJS/Runtime/ScopeObject.h

@@ -1,41 +0,0 @@
-/*
- * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#pragma once
-
-#include <LibJS/Runtime/Object.h>
-
-namespace JS {
-
-struct Variable {
-    Value value;
-    DeclarationKind declaration_kind;
-};
-
-class ScopeObject : public Object {
-    JS_OBJECT(ScopeObject, Object);
-
-public:
-    virtual Optional<Variable> get_from_scope(const FlyString&) const = 0;
-    virtual void put_to_scope(const FlyString&, Variable) = 0;
-    virtual bool delete_from_scope(FlyString const&) = 0;
-    virtual bool has_this_binding() const = 0;
-    virtual Value get_this_binding(GlobalObject&) const = 0;
-
-    ScopeObject* parent() { return m_parent; }
-    const ScopeObject* parent() const { return m_parent; }
-
-protected:
-    explicit ScopeObject(ScopeObject* parent);
-    explicit ScopeObject(GlobalObjectTag);
-
-    virtual void visit_edges(Visitor&) override;
-
-private:
-    ScopeObject* m_parent { nullptr };
-};
-
-}