Adding support for aws-efa receiver

[mitali-salvi]

Description

Adds a new awsefareceiver — a standalone OpenTelemetry receiver that collects Amazon Elastic Fabric Adapter (EFA) metrics by reading hardware counters from /sys/class/infiniband/*/ports/*/hw_counters/.

Emits 11 cumulative monotonic sum metrics per device/port (RDMA bytes, rx/tx bytes, retransmissions, connection health events) with device and port resource attributes. Supports containerized deployments via a configurable host_path.

Testing

1. Unit tests
2. Deployed the agent with configured efa receiver. added a debug exporter for demo purpose - formatted output of the data point

# ResourceMetrics #0

## Resource
| Attribute | Value |
|-----------|-------|
| `device` | `efa_0` |
| `port` | `1` |

## ScopeMetrics #0
**InstrumentationScope:** `github.com/open-telemetry/opentelemetry-collector-contrib/receiver/awsefareceiver` (Unknown)

---

### Metric #0 — `efa_impaired_remote_conn_events`
- **Description:** The number of times EFA SRD connections entered an impaired state resulting in a reduced throughput rate limit
- **Unit:** `1`
- **DataType:** Sum (Monotonic, Cumulative)
- **Start:** `2026-02-23 21:50:28.319634708 UTC`
- **Timestamp:** `2026-02-23 21:50:32.647593691 UTC`
- **Value:** `0`

### Metric #1 — `efa_rdma_read_bytes`
- **Description:** The number of bytes received using RDMA read operations
- **Unit:** `By`
- **DataType:** Sum (Monotonic, Cumulative)
- **Start:** `2026-02-23 21:50:28.319634708 UTC`
- **Timestamp:** `2026-02-23 21:50:32.647593691 UTC`
- **Value:** `0`

### Metric #2 — `efa_rdma_write_bytes`
- **Description:** The number of bytes written by other instances using RDMA write operations
- **Unit:** `By`
- **DataType:** Sum (Monotonic, Cumulative)
- **Start:** `2026-02-23 21:50:28.319634708 UTC`
- **Timestamp:** `2026-02-23 21:50:32.647593691 UTC`
- **Value:** `0`

### Metric #3 — `efa_rdma_write_recv_bytes`
- **Description:** The number of bytes received by RDMA write operations
- **Unit:** `By`
- **DataType:** Sum (Monotonic, Cumulative)
- **Start:** `2026-02-23 21:50:28.319634708 UTC`
- **Timestamp:** `2026-02-23 21:50:32.647593691 UTC`
- **Value:** `0`

### Metric #4 — `efa_retrans_bytes`
- **Description:** The number of EFA SRD bytes retransmitted
- **Unit:** `By`
- **DataType:** Sum (Monotonic, Cumulative)
- **Start:** `2026-02-23 21:50:28.319634708 UTC`
- **Timestamp:** `2026-02-23 21:50:32.647593691 UTC`
- **Value:** `0`

### Metric #5 — `efa_retrans_pkts`
- **Description:** The number of EFA SRD packets retransmitted
- **Unit:** `1`
- **DataType:** Sum (Monotonic, Cumulative)
- **Start:** `2026-02-23 21:50:28.319634708 UTC`
- **Timestamp:** `2026-02-23 21:50:32.647593691 UTC`
- **Value:** `0`

### Metric #6 — `efa_retrans_timeout_events`
- **Description:** The number of times EFA SRD traffic timed out and resulted in a network path change
- **Unit:** `1`
- **DataType:** Sum (Monotonic, Cumulative)
- **Start:** `2026-02-23 21:50:28.319634708 UTC`
- **Timestamp:** `2026-02-23 21:50:32.647593691 UTC`
- **Value:** `0`

### Metric #7 — `efa_rx_bytes`
- **Description:** The number of bytes received
- **Unit:** `By`
- **DataType:** Sum (Monotonic, Cumulative)
- **Start:** `2026-02-23 21:50:28.319634708 UTC`
- **Timestamp:** `2026-02-23 21:50:32.647593691 UTC`
- **Value:** `0`

### Metric #8 — `efa_rx_dropped`
- **Description:** The number of packets that were received and then dropped
- **Unit:** `1`
- **DataType:** Sum (Monotonic, Cumulative)
- **Start:** `2026-02-23 21:50:28.319634708 UTC`
- **Timestamp:** `2026-02-23 21:50:32.647593691 UTC`
- **Value:** `0`

### Metric #9 — `efa_tx_bytes`
- **Description:** The number of bytes transmitted
- **Unit:** `By`
- **DataType:** Sum (Monotonic, Cumulative)
- **Start:** `2026-02-23 21:50:28.319634708 UTC`
- **Timestamp:** `2026-02-23 21:50:32.647593691 UTC`
- **Value:** `0`

### Metric #10 — `efa_unresponsive_remote_events`
- **Description:** The number of times an EFA SRD remote connection was unresponsive
- **Unit:** `1`
- **DataType:** Sum (Monotonic, Cumulative)
- **Start:** `2026-02-23 21:50:28.319634708 UTC`
- **Timestamp:** `2026-02-23 21:50:32.647593691 UTC`
- **Value:** `0`

---

Documentation

README with configuration example, metrics table, and resource attributes. metadata.yaml defining all 11 metrics.