Support downloading of form submissions containing repeat group in csv format

[susmina94]

Current Situation
Currently, our system allows users to create forms with repeat groups to collect structured and repeatable data. However, when users attempt to download these form submissions, the system only supports downloading the data in non-relational formats (e.g., JSON or XML). While these formats are useful for various purposes, there is a growing demand for CSV downloads as it is a widely accepted and easily readable format, especially for data analysis and reporting purposes.

Proposed Solution
This feature request is to enhance our system's capabilities by adding the option to download form submissions containing repeat groups in CSV format. This would empower our users to seamlessly export their data in a tabular, structured, and easily analyzable format, streamlining their data processing workflows.

Expected Behavior
The expected behavior of this feature request can be summarized as follows:

1. Users should have the option to select the format in which they wish to download form submissions (e.g., CSV, JSON, XML) with CSV being the new addition.
2. The CSV download should accurately represent the hierarchical structure of the form, including repeat groups.
3. All relevant data from form submissions, including metadata and repeatable group data, should be included in the CSV file.
4. Users should have the ability to specify the structure of the CSV file, such as defining the delimiter, column headers, and data formatting options.

[robsavoye]

The CSV format comes directly from ODK Central, same as the JSON format. FMTM does no conversion at all at this stage. The format of the CSV file is defined by ODK Central. Are you suggesting we need to process the CSV download into another CSV format ?

[susmina94]

As of now, we do have csv conversions but they don't allow us to download the entire csv of the project area in a single file.
For this, Ivan has suggested a script that works well for this. However, he said it doesn't support extracting of the data from the repeat groups in the form.

But someone as a volunteer can walkthrough this issue too.

[robsavoye]

Ivan's scripts have much overlap with osm-fieldwork, and are not designed to be part of the backend of FMTM. They're fine to look at for ideas, but shouldn't be used "as is".

[robsavoye]

I have seen issues with the CSV format when dealing with existing OSM data, that I don't see with the JSON output. We should make JSON the default.

[spwoodcock]

Related to: hotosm/osm-fieldwork#257
Adding repeats to CSV should be simple now.