testing: more detailed integration tests

[jmbuhr]

Our runmanager iterator allows us to step through one by one like this: https://github.com/graeter-group/kimmdy-examples/blob/2b2b8fd5b1c579a0dc17df6a5ca39e8feec47599/wip.qmd#L174-L250

We should use the same approach to write tests for complete kimmdy runs that also test assertions during after each task instead of only checking the log at the end.

Originally posted by @jmbuhr in #476 (comment)