Documentation on addition of user's metadata in odk collect so we get proper statistics

[manjitapandey]

Currently, we haven't documented the workflow where field mappers can set their username, email and device ID so that they can be used for better tracking user's contributions and applying necessary filters.

Expected Behavior
To generate meaningful statistics and insights, it is crucial to capture user metadata alongside submitted data. Though its the odk section of documentation, still we need to document it and encourage users to update theur details before filling up form on odk collect.