Pull Request for Issue # .

Summary of Changes

This is redo of my original PR #14567 because there was some changes to component dispatcher which affected the PR.

This PR contains improvement + clean up to model classes to support both namespace and none namespace components in Joomla 4. See https://github.com/joomdonation/joomla-cms/tree/namespace-com-content/administrator/components/com_content to see namespaced com_content component by @laoneo

1. Change to Model class

• Change getName() method to support detect model name from both namespace class name and none namespace class name
• Change getTable() method to allow creating namespace table object
• Implement isCheckedOut to allow checking if a record is checked out (use in FormView class in my different PR)

2. Change to Form Model class

• Allow getting xml form and forms field from Model directory

3. Change to List Model class

• Simplify the code of getFilterForm() method
• Allow getting xml form and forms field from Model directory

4. Change to Admin Model class

• Use getColumnAlias for check_out field instead of using hardcoded name (make it consistent with other places in our code base)

Testing Instructions

This PR is for code review and discussion for Joomla 4 only. No human testing needed at the moment