[Refactoring] Moving between TreeScopes should be done by its own class.

      https://bugs.webkit.org/show_bug.cgi?id=75290

Reviewed by Ryosuke Niwa.

This change extracted Node::setTreeScopeRecursively(),
setDocumentRecursively() and a part of setDocument() into a new
class called TreeScopeAdopter. By doing this, the idea of
moving a node from scope to scope, that was originally hidden
behind the forest of Node APIs, has become clearer.

Note that this change is a preparation for Bug 59816.

No new tests. No behavioral change.

* CMakeLists.txt:
* GNUmakefile.list.am:
* Target.pri:
* WebCore.gypi:
* WebCore.vcproj/WebCore.vcproj:
* WebCore.xcodeproj/project.pbxproj:
* dom/ContainerNode.cpp: Followed the renaming.
(WebCore::ContainerNode::takeAllChildrenFrom):
(WebCore::ContainerNode::insertBefore):
(WebCore::ContainerNode::replaceChild):
(WebCore::ContainerNode::removeBetween):
(WebCore::ContainerNode::removeChildren):
(WebCore::ContainerNode::appendChild):
(WebCore::ContainerNode::parserA