Add missing links to header navigation

[kristofferfh]

We're currently missing some links in our MENU_LINKS object, we also needs to update dead/wrong links.

[kristofferfh]

Added:

• Erik ( needs merging: #52 )

Changed:

• pagehub
• contact ( needs merging: #49 )
• about ( needs merging: #50 )

[kristofferfh]

Marking this issue as closed as all current pages now have an associated link in header