LPS-50359 add TreeModel boilerplate when generating CLP model

Note that the `updateTreePath` method assigns `_treePath` before calling
the remote model. We need to assign the treePath there because the first
thing the remote updateTreePath does is to call `setTreePath` (and so we
have to guarantee that the argument given to updateTreePath will be
returned by getTreePath in subsequent calls, even if something fails).
LPS-50359 SF
LPS-50359 SF
LPS-50374 ClassNotFoundException on portal startup
LPS-50374 See com.liferay.util.SetUtil
LPS-50279 - Category names with special symbols like </b> are not displayed correctly.
LPS-50279 - General source formatting
LPS-50348 - Removing the .aui namespace from around Bootstrap
LPS-50348 - Fixing Alloy Font Awesome zip
LPS-50348 - Applying to everything else
LPS-50348 - Remove from the root_css_class
LPS-50348 - Document changes