Configure continuous integration testing of OpenEMPIRE

[chriska85]

To enhance software quality and rule out problems with commits to the master branch the project should be setup with a continuous integration system to test changes that are push to the central repository,

A prerequisite would be to setup an optimization instance that can be run smoothly without the use of a commercial solver as this would be difficult to use with the relevant CI services due to licensing. The instance "test" can be a good candidate for this.

Possible CI options are either Github Actions or Travis