Add application-signals routing rules to awsproxy translator

[liustve]

DO NOT MERGE until amazon-contributing/opentelemetry-collector-contrib#403 is merged and released and dependencies are updated.

Description of the issue

The awsproxy extension currently routes all requests to X-Ray by default, but we will need to support the new upcoming Application Signals APIs in the future as well.

Description of changes

Configure awsproxy extension to support new Application Signals APIs in the default configuration.

License

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Tests

• Update translator unit test to support new configuration.
  E2E testing verified:
• Built local CW Agent with following config:

{
  "agent": { "region": "us-east-1" },
  "logs": { "metrics_collected": { "application_signals": {} } },
  "traces": { "traces_collected": { "application_signals": {} } }
}

Ran following command:
./build/bin/linux_amd64/config-translator --input test_config.json --output /tmp/test_cwagent.toml

cat /tmp/amazon-cloudwatch-agent.yaml | grep -A 15 "additional_routing_rules"
        additional_routing_rules:
            - aws_endpoint: https://application-signals.us-east-1.api.aws
              paths:
                - list-instrumentation-configurations
                - report-instrumentation-configuration-status
              region: ""
              role_arn: ""
              service_name: application-signals
        aws_endpoint: ""
        certificate_file_path: ""
        endpoint: 0.0.0.0:2000
        imds_retries: 1
        local_mode: false
        profile: ""
        proxy_address: ""

Test X-Ray routing (default)

curl -X POST http://localhost:2000/GetSamplingRules -d '{}' -H "Content-Type: application/json"

{"NextToken":null,"SamplingRuleRecords":[{"CreatedAt":0.0,"ModifiedAt":0.0,"SamplingRule":{"Attributes":{},"FixedRate":0.05,"HTTPMethod":"*","Host":"*","Priority":10000,"ReservoirSize":1,"ResourceARN":"*","RuleARN":"arn:aws:xray:us-west-2:571600841604:sampling-rule/Default","RuleName":"Default","ServiceName":"*","ServiceType":"*","URLPath":"*","Version":1}}]}

Requirements

Before commiting your code, please do the following steps.

1. Run make fmt and make fmt-sh
2. Run make lint

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Integration Tests

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