Implement matching timelines

[LourensVeen]

This updates MUSCLE3 to the recent changes in timeline handling and adds support to the hammer for processing matching timelines. Best reviewed per commit:

• Adjust to the API change of the ymmsl Model class.
• Update libmuscle to expect macro:micro as the component timeline of the micro model, rather than having the component timeline be the parent timeline macro. Also removes absolute timelines, since we don't have those anymore.
• Implement matching timelines support in the hammer.
• The hammer now expects the timelines on all the models to be resolved before it runs, and the Manager now takes a resolved-and-then-flattened configuration. This updates everything to provide that.
• Updates to the interact example to use matching timelines, so that make test_examples works again

Finally there's a small cleanup, and the tester is now broken. Fixing it is better left to another PR though, so I've temporarily disabled the test for it.

This needs multiscale/ymmsl-python#73 to be merged for the tests to work, and addresses #417.