New 'donate' and 'donor' pages

[Amin Bandali]

Hi folks,

I just added my first pass at the two 'donate' and 'donors' pages to
the wiki, marked as draft for now:

  https://emacsconf.org/donate/

  https://emacsconf.org/donors/

I'll be working on tweaking the styling and making the donate page
a bit prettier in the near future, and potentially adding a fancy
donation widget on the page in addition to the simple donate link.
I also plan on adding one or more separate pages with more details
about the fiscal sponsorship and details about our collected funds
and our withdrawals from them.

In the mean time, please have a look and let me know your thoughts,
and any suggestions and feedback you may have about them.

When we're generally happy with them, I'll uncomment the link to the
donate page in the top nav bar to the left of the 'Edit' link there.

Thanks,
-a