[receiver/redisreceiver] Add support for Redis sentinel information

[paulojmdias]

Description

Add support for exposing Redis sentinel and mode metrics.

Redis Sentinel metrics with Redis mode:

# HELP redis_mode Redis server mode
# TYPE redis_mode gauge
redis_mode{mode="sentinel",otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 1
# HELP redis_sentinel_masters Number of masters monitored by Sentinel.
# TYPE redis_sentinel_masters gauge
redis_sentinel_masters{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 1
# HELP redis_sentinel_running_scripts Number of running Sentinel scripts.
# TYPE redis_sentinel_running_scripts gauge
redis_sentinel_running_scripts{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 0
# HELP redis_sentinel_scripts_queue_length Length of Sentinel scripts queue.
# TYPE redis_sentinel_scripts_queue_length gauge
redis_sentinel_scripts_queue_length{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 0
# HELP redis_sentinel_simulate_failure_flags Simulated failure flags bitmask.
# TYPE redis_sentinel_simulate_failure_flags gauge
redis_sentinel_simulate_failure_flags{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 0
# HELP redis_sentinel_tilt Whether Sentinel is in TILT mode (1 = tilt, 0 = normal).
# TYPE redis_sentinel_tilt gauge
redis_sentinel_tilt{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 0
# HELP redis_sentinel_tilt_since_seconds Duration in seconds of current TILT, or -1 if not in TILT mode.
# TYPE redis_sentinel_tilt_since_seconds gauge
redis_sentinel_tilt_since_seconds{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} -1
# HELP redis_sentinel_tilt_total Total TILT occurrences since start.
# TYPE redis_sentinel_tilt_total counter
redis_sentinel_tilt_total{otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 0

Redis mode (standalone):

# HELP redis_mode Redis server mode
# TYPE redis_mode gauge
redis_mode{mode="standalone",otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 1

Redis mode (cluster):

# HELP redis_mode Redis server mode
# TYPE redis_mode gauge
redis_mode{mode="cluster",otel_scope_name="github.com/open-telemetry/opentelemetry-collector-contrib/receiver/redisreceiver",otel_scope_schema_url="",otel_scope_version="0.134.0-dev"} 1

Link to tracking issue

Fixes #42365

Testing

I tested this against all the possible modes (sentinel, standalone, and cluster). The sentinel metrics are only evaluated and exposed when redis_mode:sentinel.

I also added integration tests TestIntegrationV8Sentinel for the sentinel mode.

Documentation

Updated the documentation using mdatagen