[4.4] Deprecating CMS Filesystem package

[Hackwar]

Summary of Changes

We want to switch from the CMS Filesystem package to the Framework Filesystem package. This deprecates all the classes and methods. Please notice that a few methods are still not deprecated since they would need to be copied over to the Framework package still and/or we need decisions on deprecating them.

The code in the CMS will be converted in additional PRs. I'm hoping that we can remove some code in 5.0 already with simple inheritance. See #40093, #40094, #40099 and #40104.

Testing Instructions

Codereview

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org: [https://github.com/Deprecating CMS filesystem package Manual#90]

• No documentation changes for manual.joomla.org needed

[MacJoom]

Thank you