[yashdotdev13]

Summary

Closes #721.

• Add configurable consistency mode for Consul KV requests, supporting DEFAULT, STALE, and CONSISTENT.
• Add spring.cloud.consul.config.consistency-mode, defaulting to DEFAULT.
• Apply the configured consistency mode to initial configuration reads, file-based configuration lookups, and blocking configuration watch queries.
• Preserve blocking-query parameters, including wait and index.
• Maintain existing ConsulClient overloads for compatibility.
• Update configuration property documentation and add tests for consistency-mode handling and configuration.

Testing

• Full config reactor: 55 tests passed, with 0 failures and 0 errors.
• QueryParamsArgumentResolverTests: 4 tests passed.
• ConsulConfigPropertiesTests: 3 tests passed.
• Formatting and Checkstyle validation passed.
• git diff --check passed.