move advection diffusion boundary conditions to BoundaryConditions folder and delete:

QADPress7;
QADPress27;
QADPressNEQNeighbor27;
QADVel7;
QADVel27;
QAD7;
QNoSlipADIncomp7;
QNoSlipADIncomp27;
QADVeloIncomp7;
QADVeloIncomp27;
QADPressIncomp7;
QADPressIncomp27;