Move micro_dt from coupling parameters to simulation parameters in the configuration

[IshaanDesai]

The variable to set the micro simulation dt should be a simulation parameter rather than a coupling parameter. This PR changes the configuration and also all configuration files in the examples and tests. This change also needs to be done for the two-scale-heat-conduction tutorial.

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.