Split topics into separate pages

[kmarekspartz]

No new content. Restructuring a bit in an attempt to make this a bit more digestible and more like the broadly familiar Wikipedia style of article on a single topic, with references at the bottom.

Later passes would expand the Concepts section to be prose descriptions of the topic.

[kmarekspartz]

Next step, if this is PR is taken, would be to do similar with README.md into people/*

[lorin]

Let's see how this looks!