Adds support for the validation of IndexedSets using the index

[pmlpm1986]

Fixes #2655.

Summary/Motivation:

Set members could not be validated using the index in indexed sets. This PR adds that option to allow for more complex validation rules.

Changes proposed in this PR:

• Allows validation of indexed sets to access the member and the respective index just like in Parameter objects
• Supports one- and multi-dimensional set members
• Adds tests to retain the functionality
• Revised the tutorial to illustrate the functionality.

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