Adding Disk I/O page

build-diskio.html

Signed-off-by: Belen <belenbarrospena@gmail.com>
Link to Disk I/O page and new iteration of task details pages

The previous commit added the Disk I/O information page (build-diskio.html). Linking to it from all other pages. I've also gone through a new iteration of design for the task details pages.