Minimize compiler/deprecation warnings with dune 2.8-git

There is a couple of deprecation warnings we should get rid off for the release version. See recent pipelines: https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/jobs/13567 https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/jobs/13569

Alight here is a quick summary (As of 26.05.2021):

Tests with warnings related to the GeometryTypes::cube(dim) deprecation in UG and Alu:

• test_2p_boxdfm_quads_alu
• test_2p_boxdfm_trias_alu
• test_2p_boxdfm_trias_ug
• test_2p_boxdfm_tets_ug

Tests with warnings related to the Dune::GmshReader<Grid>::read( deprecation in UG, Alu and Foam:

• test_shallowwater_poiseuilleflow
• test_gmshboundaryflag
• test_gridmanager_dgf_ug
• test_gridmanager_gmsh_e_markers_ug
• test_gridmanager_gmsh_3d_ug
• test_gridmanager_dgf_alu
• test_gmshboundaryflag_caching
• test_md_embedded_1d3d_1p1p_boxbox_average
• test_md_embedded_1d3d_1p1p_boxtpfa_average
• test_md_embedded_1d3d_1p1p_tpfabox_average
• test_md_embedded_1d3d_1p1p_tpfatpfa_surface
• test_md_embedded_1d3d_1p1p_tpfatpfa_kernel
• test_md_embedded_1d3d_1p_richards_tpfatpfa
• test_md_embedded_2d3d_fracture1p_tpfa
• test_1p_convergence_analytic_box
• test_1p_convergence_analytic_tpfa
• test_1p_pointsources_timeindependent_box_prism
• test_1p_pointsources_timeindependent_tpfa_prism
• test_1p_incompressible_tpfa_anadiff
• test_1p_fracture2d3d_mpfa
• test_1p_fracture2d3d_tpfa
• test_1p_fracture2d3d_box
• test_1p_network1d3d_box
• test_1p_network1d3d_tpfa
• test_1p2c_transport_mpfa
• test_1p2c_transport_tpfa
• test_1p2c_saltwaterintrusion_box
• test_1p2cni_conduction_tpfa
• test_1p2cni_conduction_mpfa
• test_1p2cni_conduction_box
• test_1p2cni_convection_mpfa
• test_1p2cni_convection_tpfa
• test_1p2cni_convection_box
• test_1pncni_transientbc_box_caching
• test_1pncni_transientbc_box
• test_1pncni_transientbc_tpfa_caching
• test_1pncni_transientbc_mpfa_caching
• test_1pncni_transientbc_mpfa
• test_1p2c_nonequilibrium_tpfa
• test_1pnc_maxwellstefan_tpfa
• test_2p_pointsource_adaptive_tpfa
• test_2p_adaptive_tpfa
• test_2p_fracture_mpfa
• test_2p_fracture_tpfa
• test_2p_fracture_box
• test_2pni_tpfa_simplex
• test_2pni_box_simplex
• test_2p_rotationsymmetry_dome
• test_co2_tpfa
• test_co2ni_tpfa
• test_co2_box
• test_richards_lens_tpfa_parallel_ug
• test_richards_lens_tpfa_parallel_alu
• test_richards_lens_box_parallel_ug
• test_richards_lens_box_parallel_alu
• example_1ptracer

Sequential Tests with warnings related to vtkmultiwriter.hh, start.hh, timeloop.hh (Not dune related, #869 (closed) ):

• test_dec1p
• test_3d2pmpfal
• test_impeswithamg
• test_3d2pmimetic
• test_3d2pfv
• test_dec2p2c
• test_adaptive2p2c2d

Both Sequential and Gmshreader warnings:

• test_diffusion
• test_3d2pmimeticadaptive
• test_impesadaptive
• test_impesadaptiverestart
• test_3d2pfvadaptive
• test_transport
• test_3d2pfv
• test_3d2pmpfaladaptive
• test_adaptive2p2c3d
• test_solidenergy_tpfa