Updates to About page content

[schen9981]

• Makethe purpose of CHORDS portal more of the focus of the page, and separate page into multiple sub-pages that appear in the drop down menu when hovering over “About” page on tab bar
• Some duplicate info in ‘NSF Earthcube’ and ‘CHORDS’ sections => perhaps combine into one?
• Since the “detailed info about CHORDS” links directly to the Help page, button may be not needed, or write ‘see help section’