Deallocate all the assigned memory in one go when MODFLOW finalizes

[Manangka]

To optimize the deallocation of variables when MODFLOW finalizes, this PR moves the responsibility of deallocation to a single method instead of having the responsibility per package.

Add the moment the responsibility is moved away from the packages by simply having the mem_deallocate return immediately. In the end the entire mem_deallocate method should be removed

@mjr-deltares provided a test-case to stress test the deallocation of variables.
The test case consist of 1521820 variables and a single timestep.
The time from start to till completion of the solution is about 5 seconds. The remainder of the time is spent finalizing the simulation.

The total time spent running the simulation is:

	Current deallocation	New deallocation
Total time	5m42	0m22

Checklist of items for pull request

• Replaced section above with description of pull request
• Closed issue #xxxx
• Referenced issue or pull request #xxxx
• Added new test or modified an existing test
• Ran ruff on new and modified python scripts in .doc, autotests, doc, distribution, pymake, and utils subdirectories.
• Formatted new and modified Fortran source files with fprettify
• Added doxygen comments to new and modified procedures
• Updated meson files, makefiles, and Visual Studio project files for new source files
• Updated definition files
• Updated develop.tex with a plain-language description of the bug fix, change, feature; required for changes that may affect users
• Updated input and output guide
• Removed checklist items not relevant to this pull request

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