feat: Add Object Interpretation to Capture Named Groups

[jshlbrd]

Description

• Adds named group support to object interpretation in the Capture processor

Motivation and Context

Okta's audit logs contain unusual pseudo-JSON like this ...

{
	"debugContext": {
		"debugData": {
			"behaviors": "{New Geo-Location=NEGATIVE, New Device=NEGATIVE, New IP=NEGATIVE, New State=NEGATIVE, New Country=NEGATIVE, Velocity=NEGATIVE, New City=NEGATIVE}"
		}
	}
}

... that would be much better if it were like this instead:

{
	"debugContext": {
		"debugData": {
			"behaviors": {
				"New Geo-Location": "NEGATIVE",
				"New Device": "NEGATIVE",
				"New IP": "NEGATIVE",
				"New State": "NEGATIVE",
				"New Country": "NEGATIVE",
				"Velocity": "NEGATIVE",
				"New City": "NEGATIVE"
			}
		}
	}
}

This PR makes that possible by nesting captured fields under the set_key configuration.

How Has This Been Tested?

Added new unit testing.

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:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.