Split config file into public and private config files

Closes #234

See merge request !1262

Handle optional dependency MPI by directly passing HAVE_MPI flag

See merge request !1310

Handle optional dependencies GMP, QuadMath, and Vc by directly passing HAVE_xxx flags

See merge request !1309

Handle optional dependencies (Par)METIS and (PT)Scotch by directly passing HAVE_xxx flags

See merge request !1308

[cmake] Backport Python 3.13 detection for older CMake versions

See merge request !1307

Handle optional dependency SuiteSparse by directly passing HAVE_xxx flags

Closes #252

See merge request !1294

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 !1302

They are always set to NEW by version 3.16

Do not configure non-template rst files

See merge request !1300

Use the CMAKE_CXX_STANDARD in feature tests

See merge request !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 !1293