ScyllaDB release: version 1.6

ScyllaDB 1.6, a minor release of the open-source NoSQL database compatible with Apache Cassandra, introduces several improvements, including superior performance, consistently low latency, and experimental Debian support. This release focuses on bug fixes for versions 1.6 and 1.5, urging users on older versions to upgrade. Notable features include an upgradable AMI, fetch size auto-tuning, and optimized multi-partition range scans to reduce CPU and I/O overhead. The release also brings changes to the metrics format and names, requiring users to update their monitoring tools accordingly. Key bug fixes address issues such as data streaming in repairs, bloom filter overhead reduction, and various installation and operational challenges, enhancing the overall stability and reliability of ScyllaDB.