Add a non-uniform domain decomposition variant based on geometric progression

[IshaanDesai]

The new non-uniform domain decomposition variant based on geometric progression is intended to address asymmetrical loaded scenarios such as the two-scale heat conduction.

There is a new optional configuration option, decomposition_type, which can be either uniform or nonuniform.

Checklist:

• I made sure that the CI passed before I ask for a review.
• I added a summary of the changes (compared to the last release) in the CHANGELOG.md.
• If necessary, I made changes to the documentation and/or added new content.
• I will remember to squash-and-merge, providing a useful summary of the changes of this PR.