Load Balancing Monitor Groups: Multi-Service Health Checks for Resilient Applications

Introduces Monitor Groups for Cloudflare Load Balancing, allowing the bundling of multiple health monitors (e.g., HTTP, TCP, Database) into a single logical entity. This enables sophisticated, multi-service health assessments and aggregated health scores for more intelligent failover decisions. Key features include 'must_be_healthy' for critical monitors, 'monitoring_only' for observational probes, and quorum-based health determination (more than 50% of checking data centers reporting UP). The latency metric for Dynamic Steering is updated to be the average RTT of all active, non-monitoring-only members in the Monitor Group.