Expose WS subscription chrome API.

[Hyperkid123]

Depends on: https://github.com/RedHatInsights/frontend-components/pull/2033

part of: https://issues.redhat.com/browse/RHCLOUD-33810

Changes

• exposes subscription API to WS events. Currently, only the notifications event is available
• so far the handler for notifications stays, but has to be replaced once the notif drawer is moved