Be able to define and collect meta-data on data collection

[fredhersch]

Is your feature request related to a problem? Please describe.
When running a particular assessment, it would be useful to be able to capture relevant meta-data. For example:

• start_date_time
• submit_data_time
• number_of_saves
• capture_location (automatically set the gps point)

Describe the solution you'd like
This could possible be set up in the FHIR Questionnaire itself as an extension

Describe alternatives you've considered
It could be an implementation feature that is "added" to the flow

cc: @pld to add any additional thoughts