Add reference to CIP 4.4-rt in the kernel maintenance wiki page.

Issue Background

Daniel is the 4.4-rt kernel maintainer. We need to add references to this kernel in the CIP kernel maintenance page

Issue description

• Send a request + proposal to @wagi about this topic through the cip-dev mailing list.
• Add a section about the 4.4-rt kernel and a reference in the intro paragraph.
• Add a reference to this kernel in the wiki front page.

Acceptance criteria

• Link to the section in the kernel maintenance wiki page.
• Link to the section that includes the reference to the CIP 4.4-rt kernel in the wiki front page.