If a test passed, only 1 kB of it was sent to CDash.  This
is okay to get a quick look, but not at all, if you want to
inspect things.

It looks like there once was a mode, where the
subdirectories of a FairSoft/SIMPATH installation were
structured for topics.

This mode does not exist any more.

If you install things into multiple prefixes (like with
spack), use CMAKE_PREFIX_PATH to list all the prefixes and
be done!

Bump the requirement on FairCMakeModules to 0.2.
Version 0.2 brings support for
find_package2_implicit_dependencies().

Also drop the internal fallbacks.  All important
distribution channels (FairSoft, brew, ...) have it now.
It's easy to install from source. So there isn't a good
reason to not have it installed.

First: Use find_package2_implicit_dependencies() in FairRoot and the
templates.

Second simplify FairLogger/fmt dependency handling:

FairRoot itself is now fully using CMake targets.
So there is no need to setup include directories for all
and everything.

On the other hand, projects using FairRoot are not yet
there (especially, they can't with FairRoot itself until
soon).  So let's improve include directory handling for
them.  This is especially useful on spack based builds.

See-Also: 89ccd48

fairsoft-config has two main points:
* Provide the FairSoft version.  FairRoot doesn't care at
  all.
* Provide compiler flags and C++-Level.

For the compiler flags, we just assume, that the user uses
a compatible setting, really.

For the C++-Level, we have
fairroot_check_root_cxxstd_compatibility() to check for the
compatibility with the ROOT C++-Level.
(It currently only emits a warning.)

`fairroot_check_root_cxxstd_compatibility()` is a macro to
check the compatibility of the current C++-Level with the
one of ROOT.

Recommend to use it and actually use it in the templates.

The new config mode package can easily transfer
configure/build time information to the package consumer.

Our config mode package is very minimal currently. So it
doesn't pollute anything.

So let's import (find_package) the config mode package from
inside the find module!

First for users of FairRoot:
* FairRoot exports the `CXX_STANDARD` level as
  `FairRoot_CXX_STANDARD`.
* `Check_Compiler()` uses this to set the minimum
  `CXX_STANDARD` for any users of FairRoot.  You should
  call `Check_Compiler()` after `find_package(FairRoot)`.

For FairRoot itself:
* If `CMAKE_CXX_STANDARD` is not set from outside, detect
  ROOT's `CXX_STANDARD` from its
  `target_compile_features()`.  This means, that
  `Check_Compiler()` must be called after
  `find_package(ROOT)`.
* If `CMAKE_CXX_STANDARD` is not set, try to ask
  fairsoft-config.
* Handle `PROJECT_MIN_CXX_STANDARD`.

FairCMakeModules's new FairSummary has some nice function
inspired by some of the code in FairRoot.
Let's use it in FairRoot to replace our local code.

Let's use it in the templates to make them better.