Refactor Web IDE collapsible sidebar logic

What does this MR do?

Contains refactoring to make Web IDE right-side collapsible sidebar generically reuse-able for left side.

This refactoring supports MR !21010 (closed), which will add support for the left sidebar collapsing for issue #22457 (closed)

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines
• Style guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers