Docker runtime image

[mcserep]

Currently there are 2 docker images:

1. The codecompass:dev image holds the development environment for CodeCompass.
2. The codecompass:web contains a compiled CodeCompass with its runtime dependencies and is configured to easily launch the CodeCompass_webserver binary.

Unfortunately none of them suffices to use the CodeCompass_parser binary in a dockerized production environment.

• The codecompass:dev image is not self-contained, only the dependencies are installed inside the container, the source code and the binaries of CodeCompass are outside it to support development. Starting with this image CodeCompass has to be downloaded and built first, which is unnecessary extra time spent.
• The codecompass:web image is a set up to create so called executing containers. Upon the start of a container the CodeCompass_webserver is started as a non-root codecompass user inside the container. It requires significant extra work to circumvent this and use this image as the root user without starting the webserver, so some parsing can be done. (Root privilege is required to install the dependencies of the project to be parsed.)

This pull request proposes to a third, codecompass:runtime image which contains the built CodeCompass binaries and their runtime dependencies (but not those required only for compilation time). Then the codecompass:web image can be based upon this codecompass:runtime and really only contain the dependencies of the webserver. (Smaller size.)

I have also done some completion on the documentation.