[Integration][Sonarqube] - Fix sonarQube client has no attributes metrics

[PeyGis]

Description

What - The integration was throwing an error where the self.metrics was not found in the get_all_sonarqube_analyses(). This was because each resync handler creates a new instance of the sonarQube client, causing the client to lose the state of it's saved variables. An example is when the self.metrics in the previous handler is lost in subsequent clients.
Why - Affecting the ingestion of onprem analysis kind as it relies on the metrics
How - Implemented a singleton pattern where we use one global instance of the sonarQube client across the application

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• New Integration (non-breaking change which adds a new integration)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Non-breaking change (fix of existing functionality that will not change current behavior)
• Documentation (added/updated documentation)

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API Documentation

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[Tankilevitch]

LGTM, let's make sure that for scheduled and real time there are no multi threading issues. Different event loops issues