[cmake] Use targets to communicate dependencies

What this MR does / why does DuMux need it:

This MR implements the dumux targets in a more explicit way to follow modern CMake practices (following this suggestion). In particular, it avoids relying on the dune_enable_all_packages magic, and instead communicates the dependencies explicitly.

1. Create a DuMuX libraries explicitly with dune_add_library. This is analogous to CMake's add_library but it also integrates with the dune build system to automatically generate configuration file for downstream projects.
2. Add source files to libraries with native CMake target_sources. This follows a regular CMake pattern instead of the outdated dune_library_add_sources from DUNE.
3. Express target dependencies explicitly with target_link_libraries and dune_target_enable_all_packages instead of relying on the dune build system to link against everything.
4. Make module target dumux visible to the whole project with link_libraries.

The primary motivation for this MR is to address a new warning appearing in dune-common 2.11. However, similar to the core modules, this pattern also moves DuMuX towards a build system that may provide a CMake experience in downstream modules without the dune build system. In the future, when the dune build system is ready, people should ideally only consume the DuMuX::DuMuX target after finding the dumux CMake project without having anything to do with dune and its CMake.

Notes for the reviewer

• I do not know if step 4-th is actually needed. Usually, this is used by tests, but maybe you already link explicitly, I didn't check. This simply reproduces the previous behavior.
• Current pipeline fail seems to be unrelated to this MR.
• The formatting guidelines say that I should "Use named arguments only", I do not understand what exactly this means.
• I seem to not be able to run the lecture pipeline.
• The check lists ask for a test. I assume that CI acts as a test here, right?
• The CHANGELOG entry depends whether you want to advertise the new DuMuX::DuMuX target (only present if dune-common(>=2.10)), or if you want to wait until you have full support.

Before you request a review from someone, make sure to revise the following points:

• does the new code follow the style guide?
• do the test pipelines pass? (see guide on how to run pipelines for a merge request)
• is the code you changed and/or the new code you wrote covered in the test suite? (if not, extend the existing tests or write new ones)
• does your change affect public interfaces or behavior, or, does it introduce a new feature? If so, document the change in CHANGELOG.md.
• is the list of the header includes complete? ("include what you use")
• all files have to end with a \n character. Make sure there is no \ No newline at end of file comment in "Changes" of this MR.