[STRATCONN-266] Update Boolean & Track Complete Logic

[briemcnally]

JIRA Tickets: STRATCONN-266 STRATCONN-271 STRATCONN-212

What it does

1. If a customer is passing a boolean value on a payload property that is to be sent to Adobe as either a context data variable to custom video metadata instead of passing as a 0 or 1 we will use string version of "true" or "false"
2. Removes trackComplete from Video Content Completed events as it incorrectly ends the session and discards subsequent HB calls.
3. Adds trackComplete to Video Playback Completed events per Adobe documentation, before calling sessionEnd
4. Adds support to map top level properties on track calls (messageId, anonymousId, event) and on screen (name, messageId and anonymousId) NOTE: need to uncomment anonymousId before merging and bump analytics-iOS version once LIB team publishes their updates
5. Adds support for nested context data (non-HB) variable and context metadata (HB) mapping in context.app, context.device, context.library, os, network, and screen. Customers can follow the following format for Context Data Variable Mapping:
6. Updates unit tests