[Task] Readd delete DID example

[eike-hass]

Description

During the Rebased migration we lost the 4_delete_did.rs example. We should add it again for illustration purposes.

Motivation

Demonstrate to implementers he to safely delete a DID:

Resources

Link to any resources relevant for the task such as issues, PRs, reference implementations, or specifications.

To-do list

Create a task-specific to-do list. Please link PRs that match the TODO list item behind the item after it has been submitted.

• Item one
• Item two
• Item three

Change checklist

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• The feature or fix is implemented in Rust and across all bindings whereas possible.
• The feature or fix has sufficient testing coverage
• All tests and examples build and run locally as expected
• Every piece of code has been document according to the documentation guidelines.
• If conceptual documentation (mdbook) and examples highlighting the feature exist, they are properly updated.
• If the feature is not currently documented, a documentation task Issue has been opened to address this.