Make the "category" page of the SDKs the actual overview page

[slinkydeveloper]

Right now when clicking on DEVELOP > [any] SDK, it jumps to a "category" page containing links to sub pages. This is a bit of a pointless/noisy page, and it would be nice if this page becomes the actual "Overview" page, where at the bottom we can still have the content of the category page with the links to the subpages.