Set parent ID to Edge response events (resolves #327)

[kevinlind]

Description

Add event stitching (chaining) support by setting the Event.parentId to the Event.id of the triggering event.

• Updates NetworkResponseHandler to save the list of awaiting Events, instead of just the Event IDs and timestamps. The Event is used to create a "chained" response event.
• Network responses which either do not match the request Id or the eventIndex does not match an awaiting event, do not have a parent ID for the response events.
• getLocationHint response events also have a parent ID, however the existing Event.createResponseEvent() API already sets the parent ID so no code changes were required. Test cases were added, however.

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov]

Codecov Report

Merging #361 (9f4e6a5) into dev (1cf1b14) will increase coverage by 0.02%.
The diff coverage is 100.00%.

❗ Current head 9f4e6a5 differs from pull request most recent head 0aff7be. Consider uploading reports for the commit 0aff7be to get more accurate results

@@            Coverage Diff             @@
##              dev     #361      +/-   ##
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+ Coverage   96.68%   96.70%   +0.02%     
==========================================
  Files          27       27              
  Lines        1626     1634       +8     
==========================================
+ Hits         1572     1580       +8     
  Misses         54       54              

[emdobrin]

Looks good, just some minor comments

[emdobrin]

nit: parentRequestEvent