Improve Elasticsearch resiliency with the real memory circuit breaker

Elasticsearch 7.0 introduces a new real memory circuit breaker to enhance node resiliency by using JVM functionality to accurately measure memory usage, rather than relying on estimates from existing circuit breakers. This approach aims to prevent nodes from running out of memory by rejecting requests that would surpass the memory limit, improving Elasticsearch's ability to handle significant loads and sustain workloads that were previously problematic. The real memory circuit breaker allows the system to push back against memory-intensive requests, providing feedback to clients for implementing backoff and retry mechanisms. Experiments have shown that this new implementation significantly improves Elasticsearch's stability under various conditions, making it more robust against memory overloads and enhancing its capacity to handle peak workloads.