[REFACTOR] CDPMessageBus not static anymore; fixes #1310

[lxatstariongroup]

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Description

[WIP] CDPMessageBus not static anymore

[lxatstariongroup]

Dunno if those non-disposed subscriptions have any impact and if they have to be disposed (automatically cleaned when the application closes?)

Ribbon ViewModels only close at closure of the app. No need to Dispose it as that will happen automatically.