Set the DUNE_PYTHON_WHEELHOUSE pyth even if CMAKE_INSTALL_PREFIX is set after the first run

Closes #339

See merge request !1299

Deprecate class SizeOf

See merge request !1306

[cleanup] Guard use of concept in concepts/*.hh headers

See merge request !1305

This was once added as a replacement for `sizeof...(T)`
for a variadic pack `T`, because the clang implementation
of the latter was buggy before clang 3.8. Now we require
a much newer clang version that has this but fixed for years.

[cleanup] Remove header power.hh

See merge request !1304

While these headers are already conditionally included by
`dune/common/concepts.hh` one can still include them separately.
This patch also guards these header files against individual
inclusion without available concepts support such that `headercheck`
does no longer stumble upon this.

This was deprecated in 2.9 and can be removed.
Use `Dune::power` from `dune/common/math.hh` instead.

Export the PYTHON_WHEELHOUS into the config file and cleanup MODULE_DEP_PYTHON_PATH

See merge request !1298

Increase required CMake version to 3.16

See merge request core/dune-common!1302

They are always set to NEW by version 3.16

Do not configure non-template rst files

See merge request core/dune-common!1300

Use the CMAKE_CXX_STANDARD in feature tests

See merge request core/dune-common!1301

[bugfix][plotting] Fix color bar limits.

See merge request !1297

limits are computed.

[Python] use a raw string inside 're' function

See merge request core/dune-common!1293

Move the find_package(SuiteSparse) from istl to common

See merge request core/dune-common!1284

[bugfix][CmakeBuilder] Remove ResourceWarning: unclosed file during jit.

See merge request core/dune-common!1290

move a wrongly placed changelog entry

See merge request core/dune-common!1286

Resolve "ParallelError in dune-grid Python bindings with OpenMPI"

Closes #346

See merge request core/dune-common!1280

[cleanup] Remove outdated TODO file

See merge request core/dune-common!1285

[cleanup] Remove superfluous begin private

See merge request core/dune-common!1283

dune-add-spdx: utility script to add SPDX headers to files

See merge request core/dune-common!1210