Add some useful extra constructors to ForceProviderInput

Up to now there was just a single constructor for ForceProviderInput that would require all parameters that the class holds. This constructor is fine for using it in the MD loop, where all parameters need to be passed. However, using that full constructor in test code for a force provider (as e.g. in applied-forces/tests/electricfield.cpp) requires to change that test each time the constructor is extended in the future, although such changes will likely be unrelated to the test. Adding a few basic constructors with a limited number of arguments for typical use cases solves that issue.