ECS Fargate Docker id updates

[jtduffy]

Resolves #2047

Updates to the way ECS Fargate docker ids are detected:

• The ECS fargate endpoint must be checked, even if a docker id was found using cgroups
• If found, it must reported as a new vendor in the utilization payload (details in the spec)
• Both the cgroup docker id and ECS fargate docker id will be reported if both are present

The metadata environment variables which specify the endpoints are unchanged, as is the order in which to check them (ie: check the v4 endpoint prior to checking the un-versioned endpoint). The response JSON is also unchanged.

This will be merged after full stack testing on AWS is performed.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 80.64516% with 6 lines in your changes missing coverage. Please review.

Project coverage is 70.57%. Comparing base (8308389) to head (7271111).

Files with missing lines	Patch %	Lines
...ava/com/newrelic/agent/utilization/DockerData.java	64.70%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #2050   +/-   ##
=========================================
  Coverage     70.57%   70.57%           
- Complexity     9875     9878    +3     
=========================================
  Files           829      829           
  Lines         39945    39958   +13     
  Branches       6078     6080    +2     
=========================================
+ Hits          28191    28202   +11     
+ Misses         9024     9023    -1     
- Partials       2730     2733    +3     

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