Reading global values from preCICE and providing in "global dictionary"

[uekerman]

Motivated from @ahmed-h-elsheikh s case, but this could be a general solution to many applications.
We could first work with a one-vertex dummy helper mesh in preCICE and later use precice/precice#202

We are not sure yet if this "global dictionary" is really accessible, but investigating this could be helpful.

Connected to #277

[MakisH]

Do you mean that we need a subdictionary in preciceDict to specify which global values we want to exchange via the preCICE "global values exchange" feature?

Or do you mean creating a similar feature directly in the adapter, which would go via a single point mesh? Would the latter make sense in the long run?

[mosayebshams]

In our case the "global value (an action)" is specific to an OpenFOAM patch, which ideally, we want the value to be directly communicated with the patch rather than we convert the action to a patch field (within our python environment) and then communicate the whole field via preCICE.