Add support for iobroker.notification-manager

[randomname32]

Please evaluate if it is possible to add this adapter to the supported messaging adapters of https://github.com/foxriver76/ioBroker.notification-manager

From the documentation of iobroker.notification-manager:

This adapter allows to redirect the ioBroker internal Notifications to messenger adapters which support the Notification System. If you are missing an adapter, please open a ticket on the corresponding adapter.
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Please set the common.supportedMessages.notifications flag to true in your io-package.json.

I can contribute by testing the new feature and code-reviewing

Thank you!