Add a Dockerfile to automate server compilation testing

The server/test/docker folder contains Dockerfile templates used for testing that the epdfinfo server compiles correctly on various operating systems (more details here).

To see the list of operating systems where compilation testing is supported, run make server-test-supported. To see the list of operating systems where testing is unsupported, run make server-test-unsupported. To add support, look into the server/test/docker/templates folder (ubuntu files are a good example to refer to)