Add NIH R01 news post, PDF to science page, and update FAQ for Letters of Support

[jchodera]

This PR adds a News post discussing the NIH R01 we recently submitted to fund the Open Force Field Initiative:

I've also added the PDF of the science component of the R01 to the Science page:

Finally, I've updated the FAQ to clarify that we are supportive of other force field efforts and provide information on requesting a Letter of Support:

[mrshirts]

Sounds good. I would change "seeks" to "applies for" - seeks sounds kind of needy. I have on my todo list to email back the people who contributed letters with this post so they can see the grant once this gets posted (if people want to email their particular contacts, and I just focus on the general ones, that works for me too.

[jchodera]

Fixed!