Adds a `make lint-license` command that will crawl through the Golang and
Javascript dependencies, trying to automatically determine the license of each
dependency. If any dependencies have incompatible licensing (or if the
automatic detection fails), the tool will print an error and exit with a
non-zero status code. After a successful run, the
docs/third-party/dependencies.md file will be updated with attribution
information as determined by the crawl.
The configuration file has been bootstrapped with the manual analysis needed for
all of the existing dependencies.
* add graceful server shutdown
Also refactors server to use `http.Server` instead of the global
http.ListenAndServe method. In the future it allows us to set
ratelimits and timeouts for http connections.
