[connector/otlpjson] Add connector's implementations

[ChrsMark]

Description:

This is the 2nd PR for the new otlpjson connector (#34208). Adds the ConsumeLogs methods for the logs, metrics and traces respective connector types.

At the moment, the connector retrieves the otlp json from the incoming Log's Body. This is not configurable yet. It can be decided if that needs to be.

In addition, there is no attribute/metadata extraction/transfer from the incoming Log. This can be added in future iterations.

Link to tracking Issue: #34208 #34239

Testing: Added.

Documentation: ~

[ChrsMark]

How to test this manually

1. Use the folllowing builder config:

dist:
  name: otelcol-dev-bin
  description: Basic OpenTelemetry collector distribution for Developers
  output_path: ./otelcol-dev
  otelcol_version: 0.105.0

exporters:
  - gomod: go.opentelemetry.io/collector/exporter/debugexporter v0.105.0

receivers:
  - gomod: github.com/open-telemetry/opentelemetry-collector-contrib/receiver/filelogreceiver v0.105.0

connectors:
  - gomod: github.com/open-telemetry/opentelemetry-collector-contrib/connector/otlpjsonconnector v0.105.0

replaces:
  - github.com/open-telemetry/opentelemetry-collector-contrib/connector/otlpjsonconnector => ~/go/src/github.com/open-telemetry/opentelemetry-collector-contrib/connector/otlpjsonconnector

2. Use the following Collector's config:

receivers:
  filelog:
    include:
      - /var/log/pods/prod_my-target-pod_49cc7c1fd3702c40b2686ea7486091d3/my-target-pod/1.log

exporters:
  debug:
    verbosity: detailed

connectors:
  otlpjson:

service:
  pipelines:
    logs/raw:
      receivers: [filelog]
      exporters: [otlpjson]
    metrics/otlp:
      receivers: [ otlpjson ]
      exporters: [ debug ]
    logs/otlp:
      receivers: [ otlpjson ]
      exporters: [ debug ]
    traces/otlp:
      receivers: [ otlpjson ]
      exporters: [ debug ]

3. Run the Collector: ./otelcol-dev/otelcol-dev-bin --config=config.yaml
4. Write some lines to the log file:

> echo '{"resourceSpans":[{"resource":{"attributes":[{"key":"resource-attr","value":{"stringValue":"resource-attr-val-1"}}]},"scopeSpans":[{"scope":{},"spans":[{"traceId":"","spanId":"","parentSpanId":"","name":"operationA","startTimeUnixNano":"1581452772000000321","endTimeUnixNano":"1581452773000000789","droppedAttributesCount":1,"events":[{"timeUnixNano":"1581452773000000123","name":"event-with-attr","attributes":[{"key":"span-event-attr","value":{"stringValue":"span-event-attr-val"}}],"droppedAttributesCount":2},{"timeUnixNano":"1581452773000000123","name":"event","droppedAttributesCount":2}],"droppedEventsCount":1,"status":{"message":"status-cancelled","code":2}},{"traceId":"","spanId":"","parentSpanId":"","name":"operationB","startTimeUnixNano":"1581452772000000321","endTimeUnixNano":"1581452773000000789","links":[{"traceId":"","spanId":"","attributes":[{"key":"span-link-attr","value":{"stringValue":"span-link-attr-val"}}],"droppedAttributesCount":4},{"traceId":"","spanId":"","droppedAttributesCount":1}],"droppedLinksCount":3,"status":{}}]}]}]}' >> /var/log/pods/prod_my-target-pod_49cc7c1fd3702c40b2686ea7486091d3/my-target-pod/1.log
> echo '{"resourceLogs":[{"resource":{"attributes":[{"key":"resource-attr","value":{"stringValue":"resource-attr-val-1"}}]},"scopeLogs":[{"scope":{},"logRecords":[{"timeUnixNano":"1581452773000000789","severityNumber":9,"severityText":"Info","body":{"stringValue":"This is a log message"},"attributes":[{"key":"app","value":{"stringValue":"server"}},{"key":"instance_num","value":{"intValue":"1"}}],"droppedAttributesCount":1,"traceId":"08040201000000000000000000000000","spanId":"0102040800000000"},{"timeUnixNano":"1581452773000000789","severityNumber":9,"severityText":"Info","body":{"stringValue":"something happened"},"attributes":[{"key":"customer","value":{"stringValue":"acme"}},{"key":"env","value":{"stringValue":"dev"}}],"droppedAttributesCount":1,"traceId":"","spanId":""}]}]}]}' >> /var/log/pods/prod_my-target-pod_49cc7c1fd3702c40b2686ea7486091d3/my-target-pod/1.log
> echo '{"resourceMetrics":[{"resource":{"attributes":[{"key":"resource-attr","value":{"stringValue":"resource-attr-val-1"}}]},"scopeMetrics":[{"scope":{},"metrics":[{"name":"counter-int","unit":"1","sum":{"dataPoints":[{"attributes":[{"key":"label-1","value":{"stringValue":"label-value-1"}}],"startTimeUnixNano":"1581452773000000789","timeUnixNano":"1581452773000000789","asInt":"123"},{"attributes":[{"key":"label-2","value":{"stringValue":"label-value-2"}}],"startTimeUnixNano":"1581452772000000321","timeUnixNano":"1581452773000000789","asInt":"456"}],"aggregationTemporality":2,"isMonotonic":true}},{"name":"counter-int","unit":"1","sum":{"dataPoints":[{"attributes":[{"key":"label-1","value":{"stringValue":"label-value-1"}}],"startTimeUnixNano":"1581452772000000321","timeUnixNano":"1581452773000000789","asInt":"123"},{"attributes":[{"key":"label-2","value":{"stringValue":"label-value-2"}}],"startTimeUnixNano":"1581452772000000321","timeUnixNano":"1581452773000000789","asInt":"456"}],"aggregationTemporality":2,"isMonotonic":true}}]}]}]}' >> /var/log/pods/prod_my-target-pod_49cc7c1fd3702c40b2686ea7486091d3/my-target-pod/1.log

5. Verify in the console that otlp logs, metrics, traces are properly extracted.