feat(Health): add property to indicate whether a data point was manually entered by the user

[luucasberger]

Adds a property to HealthDataPoint that indicates whether a data point was manually entered by the user:

• (Android) Adds a key named 'user_entered' to the map that is created from each extracted Fitness data point. This key contains a bool value that indicates whether the data point was manually entered by the user or not.
• (iOS) Adds a key named 'user_entered' to the map that is created from each extracted Health data sample. This key contains a bool value that indicates whether the data sample was manually entered by the user or not.
• Adds a property named '_isUserEntered' to the HealthDataPoint model to indicate whether the data point was manually entered by the user.
• Adds 'userEntered' property to all HealthDataPoint object creations in HealthFactory.

Closes #684 , closes #670 , closes #590 , closes #396 , closes #293

[bardram]

@luucasberger - I think this is covered by PR #920 which has been merged and released in version 10.x. Please check.