Optional output of mapped mesh

[fsimonis]

Main changes of this PR

Depends on #195

This PR makes the output of solver B optional, which can be useful if the result isn't needed.
It also adds general>write-mapped to the setup which controls this for the entire case.
Turning it off, also turns off the generation of postprocessing scripts for obvious reasons.

Author's checklist

• I used the pre-commit hook and used pre-commit run --all to apply all available hooks.
• I added a test to cover the proposed changes in our test suite.
• I updated the documentation in docs/README.md.
• I updated potential breaking changes in the tutorial precice/tutorials/aste-turbine.

[fsimonis]

Rebased on the current #195