[documentation] Fix links to older releases

[kinow]

Reported by @charlio86 at a group meeting, probably broken due to !399.

Note from @manuel-g-castro (thanks!):

For those that want to reach the documentation, the correct links for each of the maintened versions that are not working are:

• https://autosubmit.readthedocs.io/en/v3.14.0/
• https://autosubmit.readthedocs.io/en/v3.13.0/

[kinow]

I will add the redirects and see if that solves all the broken links. But will have to do that later as we need to finish the EDITO work first. Setting milestone to 4.2.0 (happy if anyone beats me to it)