TH2M PTM generalized initialisation for phase transition models

See merge request ogs/ogs!3770

[MeL/IO] XDMF: Fix missing header

See merge request ogs/ogs!3769

Günther Salzer Model

See merge request ogs/ogs!3747

Introduced initial stress capability in MFront orthotropic linear elasticity.

See merge request ogs/ogs!3765

TH2M: Extract constitutive variables.

See merge request ogs/ogs!3763

[ci] Use git clang-format and merged result pipelines.

See merge request ogs/ogs!3761

A class of variables similar to those stored in the
integration point data but needed only temporary for
the assembly process.

If git clang-format is not available the check always passes. I did
not found a way to let pre-commit mark the check as skipped or not
available to indicate that the checks are not run complete.

https://docs.gitlab.com/ee/ci/pipelines/pipelines_for_merged_results.html

TH2M: Separate non-constant solid phase vol.frac.

See merge request ogs/ogs!3760

The propertie belongs into the material models.
Computations in near future will require only constant
solid phase volume fraction, so the switch is added
to separate constant and non-constant parts.

[MeL/Elements] Calculate content on the fly - saves memory.

See merge request ogs/ogs!3741

Speedup Dirichlet BCs for deactivated subdomains

See merge request ogs/ogs!3756

The getContent() method is used only on very few
places. Especially, it isn't used in the computation
of any THMC processes. So the content doesn't need
to be stored which saves memory. Furthermore, the time
time for reading / initializing a mesh is reduced.

In a hex mesh with 100x100x100 elements this saves
2.6% of storage and circa 25% time.

Small fixes

See merge request ogs/ogs!3754

Seems to be a compiler/c++lib "bug".