Send SIGTERM to parent process

[timvlaer]

Issue #, if available:
See #1667
This PR is a draft, still trying to get this tested on my device.

Description of changes:

Why is this change necessary:

How was this change tested:

• Updated or added new unit tests.
• Updated or added new integration tests.
• Updated or added new end-to-end tests.
• If my code makes a remote network call, it was tested with a proxy.

Any additional information or context required to review the change:

Documentation Checklist:

• Updated the README if applicable.

Compatibility Checklist:

• I confirm that the change is backwards compatible.
• Any modification or deletion of public interfaces does not impact other plugin components.
• For external library version updates, I have reviewed its change logs and Nucleus does not consume
  any deprecated method or type.

Refer to Compatibility Guidelines for more information.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.