[feature]: added external authentication to types for UserCommon

[foxriver76]

Link the feature issue which is closed by this PR

closes #1286

Implementation details

Added externalAuthentication optional property to UserCommon. It is Record<string, unknown> to allow for different external auths by name and the structure needs to be defined per implementation.

Tests

• [x] I have added tests to test this feature
• [ ] It is not possible to test this feature

Documentation

• [ ] I have documented the new feature

Documenting it on the type level should be enough IMO, specific implementations should document the further structure then, like https://github.com/ioBroker/webserver/pull/7

[GermanBluefox]

@foxriver76 do you have an example, how to use this?

[foxriver76]

@foxriver76 do you have an example, how to use this?

Sure, as mentioned in the initial comment https://github.com/ioBroker/webserver/pull/7 and the corresponding admin PR