throw if lb boundaries do not fit lb algorithm

[christophlohrmann]

Fixes #4467

Test this by setting up a myconfig.hpp with LB_BOUNDARIES xor LB_BOUNDARIES_GPU and running

import unittest as ut
from espressomd import System, lb, lbboundaries, shapes
import espressomd


class TestBoundaryFeatureCombo(ut.TestCase):
    system = System(box_l=3 * [10])
    system.time_step = 1
    lb_bound = lbboundaries.LBBoundary(shape=shapes.Wall(normal=[1, 0, 0], dist=3))
    lb_params = {'agrid': 1.,
                 'dens': 1.,
                 'visc': 1.,
                 'tau': system.time_step}

    def test_errors(self):
        if espressomd.has_features(["CUDA", "LB_BOUNDARIES"]) and espressomd.missing_features(["LB_BOUNDARIES_GPU"]):
            lbf = lb.LBFluidGPU(**self.lb_params)
            self.system.actors.add(lbf)
            with self.assertRaises(Exception):
                self.system.lbboundaries.add(self.lb_bound)
        if espressomd.has_features(["LB_BOUNDARIES_GPU"]) and espressomd.missing_features(["LB_BOUNDARIES"]):
            lbf = lb.LBFluid(**self.lb_params)
            self.system.actors.add(lbf)
            with self.assertRaises(Exception):
                self.system.lbboundaries.add(self.lb_bound)

if __name__ == '__main__':
    ut.main()

[jngrad]

Thanks!