Implement postponed work packages from #596

### 📝 Description of the feature

Some work packages were postponed from #596 (see TODOs):
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- Access to all node properties
- [x] Method `node.get_properties()` was exposed to the public `Node` API
- Access to top level nodes / systems of a `ParametricDesignStudy`. Make activation / deactivation of execution blocks more convenient.
- [x] improve documentation
- [x] API of `ParametricDesignStudy` was extendend for functionality to [extend / remove / access] instances and execution blocks [+ reorder]
- [x] API of `ExecutableBlock` was extended for methods to [access / remove / add] instances, modify execution options, set block [active / inactive / apply respective execution options]
- Create wrappers around relevant settings for specific algorithm systems (Sensitivity, Robustness, AMOP, OCO, MOP...). Wrappers should provide convenient access to specified properties, be extensible (allow setting additional properties) and be reusable via `Node.set_property()`.
- [ ] TODO: individual settings classes, docstring update
- Additional design study templates:
- [ ] TODO: Explicit DesignStudyTemplate with proxy solver
- [x] Extend optional arguments of OptimizationOnMOPTemplate (number of best designs to validate, mop extrapolation type)
- Editable settings of the design studies (specifically settings passed to the constructor).
- [x] NOT implemented directly. This is possible via direct access to the nodes (API extended, documentation improved).
Additionally, `set_properties` method was implemented. The intended use case would be:
1. Prepare the convenience settings template
2. Use settings template `convert_to_dict` method, converting properties to correct format
3. Access the instance to be modified using extended `ParametricDesignStudy` API
4. Pass output of the `convert_to_dict` method to the `set_properties` method.
- [x] callback setter of `ProxySolverManagedParametricSystem` implemented
- Example and/or improved documentation on how to create a `ParametricDesignStudy` from an existing optiSLang project.
- [x] Example

### 💡 Steps for implementing the feature

- [ ] TODO: individual settings classes, docstring update
- [ ] TODO: Explicit DesignStudyTemplate with proxy solver

### 🔗 Useful links and references

_No response_

Start by reviewing issue #596 and the two remaining TODOs: individual settings classes with updated docstrings, and an explicit DesignStudyTemplate with a proxy solver. Inspect the existing ProxySolverManagedParametricSystem callback setter and related design-study APIs. Done means both postponed items are implemented and their documentation is updated.

Written by the indexing model from the issue text.