Set stable `ExternalAnalysisID` for all non-GitHub analysis scrapers

[adityathebe]

AWS (Trusted Advisor, Config Rules, EC2 Analyzer), Azure (Advisor), GCP (Security Center) and Trivy scrapers all produce AnalysisResult without setting ExternalAnalysisID, falling back to the config_id::analyzer composite key for deduplication. Each source needs to be investigated for a native stable identifier to use instead.