Add Elmer as a fluid and solid participant to the flow-over-heated-plate tutorial

[IshaanDesai]

In a contribution to the Elmer adapter, the Elmer case setup for fluid and solid participants for the flow-over-heated-plate tutorial were updated: https://github.com/precice/elmer-adapter/pull/4 Until now the entire tutorial lived in the adapter repository, but as part of the current update, it is now being moved to the tutorials repository, to ensure maintainability.

The updates were done by @tapegoji

Checklist:

• [ ] I added a summary of any user-facing changes (compared to the last release) in the changelog-entries/<PRnumber>.md.
• [ ] I will remember to squash-and-merge, providing a useful summary of the changes of this PR.