Add info about adaptivity tuning parameters

[IshaanDesai]

In the configuration documentation, information about the adaptivity tuning parameters was missing. This PR adds information, which is taken from this paper.

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.

[mathiskelm]

In the parameter table above, I would specify both constants C_r and C_c as 0 <= C < 1.