Add link for PHP

[alanseiden]

Closes #130

[kadler]

I agree we should have a link for PHP, but I'm not sure that's the correct place for it. The contents section there is just a table of contents section for the docs. Adding a whole separate PHP page just to link to the IBM Support page seems like a waste, though. @ThePrez what are your thoughts?

[ThePrez]

I have similar thoughts. The contents section is really to navigate the current site. We could call out "external link" or something like that, but it's really just meant to be a table of contents.

I'd really like to have a PHP section in the docs but we haven't had any contributors step up. I'd suggest moving this into a different/new section for external links. Maybe the existing Links and other IBM i Open Source resources?

[alanseiden]

What I perceived was that the other languages were there (Python, Node). People would expect PHP to be there in the same category and not know about IBM's distinction between the types of documentation.