Add Belgium Waterinfo VMM water level bridge

[clemensv]

Belgium Waterinfo VMM Water Level Bridge

Streams real-time water level data from the Belgian Waterinfo.be KIWIS API (VMM provider) to Apache Kafka via CloudEvents.

Data Sources

• Stations (~1,785): All VMM monitoring stations across Flanders/Belgium
• Water Level 15-min (~1,109 time series): Real-time water level (H) in meters

Architecture

• Namespace: BE.Vlaanderen.Waterinfo.VMM
• Protocol: KISTERS KIWIS QueryServices (getTimeseriesValueLayer for bulk latest values)
• Polls every 15 minutes with change detection
• Sends station reference data as CloudEvents at startup
• No authentication required for standard polling

Tests

• 19 unit tests (data models, initialization, connection string parsing, KIWIS config)
• 9 e2e tests (real API verification: stations, value layer, coordinates, timeseries, groups)
• 3 container tests (KafkaContainer with mocked and live API variants)
• All 31 tests pass

Files

• 28 files, 1,429 lines added
• Complete project: xreg schema, data models, producer client, main poller, CLI entry point
• Docker + Azure Event Hubs deployment support
• Full documentation (README, EVENTS, CONTAINER)