The "commit_links" table is now called "commit_edges".
There is now a "metrics" table that run measurements have a foreign key
to. This provides canonical metric metadata and will speed up the
initial graph page (before any real data arrives). For now, it will be
overwritten with each new run, but more nuanced config options may be
added later.
Now, the server sends the runner pretty much all run metadata. This way,
the reservation the server makes for the runner is accurate, providing
the runner responds with the same metadata it was sent. It also means
that only the server's system clock is relevant for tie breakers, and a
run's duration spans from the moment it is reserved to the moment it is
saved.
Also, the bench method is now always called `bench_method` and a
human-readable description is stored in the database for each run.
With the linux kernel commits, this reduced the time to update commit
tracked flags from >60s to 44s, but this requires further testing before
committing to the indices.
