DEM, CFD-DEM periodic boundary fix

[OGaboriault]

Description of the problem

• Periodic boundary conditions were not working when they were not declare as the last BC in the parameter file.
• BC_type was changing value at every BC being parsed. "BC_type" was being checked later in the code (in dem.cc) to set "has_periodic_boundaries" to true or false. If the periodic BC was being declared before the an other BC, "BC_type" was not set to "BoundaryType::periodic", thus "has_periodic_boundaries = false".

Description of the solution

• We store every BC type in a vector (BC_types).
• We check each component of that vector, if it's equal to "BoundaryType::periodic", then "has_periodic_boundaries = true"

How Has This Been Tested?

• Every test is passing.
• I can modify one of our current test to add a dummy BC at the end of a parameter file, so that it check for this kind of problem.

Comments

• Not gonna lie, it was not hard a bug spot in the code... wish I had spot this mistake earlier in my results....

[blaisb]

@OGaboriault I think this needs a CHANGELOG entry