R1:64472dd7b8da

Adding Ponder-related files.

Summary:
Ponder is similar in spirit to the Wiki tool, but uses a Q&A
format and up/downvotes to signal user sentiment. Popular
questions are moved to the top of the feed on a 5-minute
cycle based on age (younger is better) and vote count (higher
is better).

Pre-apologies for noob diff.

Test Plan:
- `./bin/phd list` Should include `PonderHeatDaemon`; phd launch it
if necessary.

- Navigate to /ponder/ ; observe sanity when adding questions,
voting on them, and adding…