WEB: Moving pandas blog to the website
Moving the pandas blog posts (now in a separate repo/project) to the `web/community/blog/` in our website. The static site generator we're using for the web, renders them automatically using our layout:

![pandas_blog_2](https://user-images.githubusercontent.com/10058240/78026717-01a10b80-7354-11ea-830e-65af77ed4838.png)

The posts list doesn't have much visual change, just links to the new path:

![pandas_blog_1](https://user-images.githubusercontent.com/10058240/78026785-1b425300-7354-11ea-8cdd-ab632b62d41e.png)

The main change here, besides adding the posts markdown files (and images) is that the static site generator is now able to not only fetch from rss, but also from the file system.

CC: @TomAugspurger 

Btw @TomAugspurger , I increased the number of posts we show in the list, and see that there are some about dask-ml and other things unrelated to pandas being fetched from your blog. Would be great if you can add a pandas tag to your blog, so we only fetch the relevant content.