Dockerfile to run uts-server, a micro RFC3161-compliant timestamp server
written in C [1]. Please see [2] for details on the configuration file
provided. This is somewhat based on [3] but civetweb is provided via a Debian
package.

Since Docker containers are not supposed to contain secrets, one must expose
a directory with cryptographic material for the Timestamp Authority on the host
machine, e.g. through the VOLUME directive.

It can be tested from a terminal as follows.

    $ docker build -t uts-server:0.2.1 .
    $ docker run -v /path/to/your/conf:/etc/uts-server -p 2020:2020 \
        uts-server:0.2.1 -D -c /etc/uts-server/uts.conf

A page should appear at http://localhost:2020 explaining how to use the
service.

[1] https://github.com/kakwa/uts-server
[2] https://uts-server.readthedocs.io/en/latest/configure.html
[3] https://github.com/nicholasamorim/dockerfile-uts-server