Provide support for componentization of consistency

[jeanpmathes]

This PR provides required changes for the "Componentization of Model Consistency" thesis. It aims to allow creating Vitruvius viewtypes using NeoJoin and use this viewtypes in a change propagation specification. This required two major parts:

1. Change propagation specifications can be assigned a level. By default, all change propagation specifications have level zero. Before a change propagation specification of a level N greater than zero is executed, all relevant change propagations of lower levels are executed first. This allows to ensure that one component/part of a VSUM is fully consistent internally before a change propagation from or to that component to other components is executed.
2. Before change propagations are executed, a snapshot/copy of the VSUM state is created. These snapshots are then provided to the change propagation specification so that it can use both the current state and the state before the changes it propagates were applied.

This two major changes are accompanied by smaller changes, especially to change propagation. This includes a new method to the ChangePropagationSpecification interface which allows to receive all changes at once instead of a method call per individual change. These could lead to changes in behavior for existing code, but generally the additions were written in a way to minimize that.

The changed interfaces require implementers to implement new methods, this specifically impacts the types ResourceAccess, ChangeRecordingModelRepository, PersistableCorrespondenceModel and ChangePropagationSpecificationProvider. For Vitruv, the PR vitruv-tools/Vitruv#893 implements the necessary methods.

This fork of the methodologist template shows how to use new systems for viewtypes, it requires the thesis implementation.