Location and name/format of the preciceDict

[MakisH]

We currently read the adapter config as ./system/preciceDict, as an OpenFOAM dictionary.

To conform with the adapter guidelines, we could further investigate if it is possible to:

1. Read an OpenFOAM dictionary from ./preciceDict (check the IOObject constructor, which specifies runTime_.system())
2. Read a JSON/YAML file called precice-adapter-config.{json|yaml}.