Retrieve alert KPIs from backend

[karolikl]

Currently, the number of alerts in Analytics is static:

The number of alerts needs to be retrieved from the backend: GET /api/KPI/{from}/{to}

Format of response: { "caseReports": { "totalNumberOfReports": 2056, "reportedHealthRisks": [ { "name": "Cholera", "numberOfReports": 736 }, { "name": "Acute Watery Diarrhea", "numberOfReports": 680 }, { "name": "Measels", "numberOfReports": 640 } ] }, "dataCollectors": { "totalNumberOfDataCollectors": 24, "activeDataCollectors": 9, "inactiveDataCollectors": 15 }, "alerts": { "totalNumberOfAlerts": 3, "alertsPerHealthRisk": [ { "healthRisk": "SomeHealthRisk", "numberOfReports": 1 }, { "healthRisk": "SomeHealthRisk", "numberOfReports": 1 }, { "healthRisk": "SomeHealthRisk", "numberOfReports": 1 } ] } }