:: Informational API for tilde.institute ::

This allows one to query information and stats via HTTP requests. GET and
HEAD methods are allowed. All others will receive a 405 response. Responses
will be cached for a short period of time (5m?). Subsequent queries in that
time frame will be served from the cache.

Not finished. Currently planning:

    /
        - Information on endpoints and purpose

    /[plain|json]
        - Response formats

    /$FMT/osversion
        - OpenBSD version

    /$FMT/pkgs
        - Installed packages

    /$FMT/query
        ?pkg=[a-zA-Z0-9+]
            - Check if a package is installed.

    /$FMT/uptime
        - Uptime and Load

    /$FMT/usercount
        - Number of registered user accounts

    /$FMT/users
        - List of users (maybe CSV for plaintext?) and ancillary information


I'll use some kind of fast hash as an etag.

Probably going to add more endpoints.