add(vulnerabilities): count of applications for a given dates and environment

* This can help teams to see why changes in number of vulnerabilites could dramaticly change

Author: ybelMekk

internal/database/gensql/vulnerability.sql.go

@@ -7,6 +7,7 @@ SELECT
     sum(low) AS low,
     sum(unassigned) AS unassigned,
     sum(risk_score) AS risk_score,
+    COUNT(DISTINCT dependencytrack_project_id) AS count,
     date
 FROM
     vulnerability_metrics
@@ -32,6 +33,7 @@ SELECT
     sum(low) AS low,
     sum(unassigned) AS unassigned,
     sum(risk_score) AS risk_score,
+    COUNT(DISTINCT dependencytrack_project_id) AS count,
     date
 FROM
     vulnerability_metrics

internal/database/queries/vulnerability.sql

@@ -416,6 +416,9 @@ type VulnerabilityMetric {
 
   "The weighted severity score calculated from the number of vulnerabilities."
   riskScore: Int!
+
+  "The number of applications with vulnerabilities."
+  count: Int!
 }
 
 "Slack alerts channel type."