License update

[thomas-robinson]

Description

• Updates the license file for Apache 2.0.
• Updates the header file on code files for Apache 2.0
• Removes the license header on files that are already licensed with different licenses: mpp/mpp_memuse.c random_numbers/mersennetwister.F90

Fixes #1683

How Has This Been Tested?
Tested with the CI

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules
• New check tests, if applicable, are included
• make distcheck passes

[thomas-robinson]

I updated the code with main and it should be good to review/merge.