[cmake] MSVCs Multi-ToolTask scheduler for build parallelism and better ccache.

See merge request !4306

Enables ccache also on Xcode (not tested).

Implementation from Professional CMake, 13th edition, by C. Scott.

Is used automatically in Visual Studio.
When building on the command line supply the /m option, e.g.:
cmake --build . -- /m

Will speed-up wheel builds (all other CI jobs use Ninja).

[T] Added metadata for website

See merge request !4305

Python wrapper for OGS commandline tools

See merge request !4285

Fix/silence cmake-lint complaints

See merge request !4301

A set of small fixes.

See merge request !4292

Tom Fischer authored Sep 26, 2022 and Dmitry Yu. Naumov committed Sep 29, 2022

[MPL] FormEigenVector: Avoid warning 'Found a exit path from function with non-void return type that has missing return statement'

A range would be even better...

Reduced the number of headers including ConfigTree

See merge request !4290

Improve the documentation of optional parameters

See merge request !4297

[PL/LiquidFlow] Make process per default non-linear

See merge request !4203

Convenient access to MFront's tangent operator blocks data

See merge request !4282

[ci] Fix master

See merge request !4293

CI_COMMIT_MESSAGE not available for merge request pipelines.

[ci] Fixing incomplete cpm cache.

See merge request !4291

Image does not contain any library. Fixes an issue where the job ran
on envinfs and there were some libraries installed system-wide.