feat/support-ext-api-keys

[dancixx]

All Submissions:

• Contributions should target the dev branch. Did you create your branch from dev?
• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

New Feature Submissions:

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Changes to Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your core changes, as applicable?
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[generall]

I propose more general solution #273

[dancixx]

I propose more general solution #273

Rebased and tests are adjusted.