Ft enable xls parsing

[khalifan-kfan]

Description

This PR enables the user to update the Enketo submission form, It mainly solves the issue #248

Discussion

#248

Screenshots / Videos

[chrismclarke]

Thanks @khalifan-kfan , lots of really great progress here considering all the extra work that's gone into the API endpoints.

I can confirm that the full process is working for me to upload an xls file and have it converted to XML and then enketo form.

I've added a couple minor additions,
96a7eef - this converts the HTTP request from subscriptions to promise using an rxjs utility method called firstValueFrom. This is useful in HTTP request where you know you are just going to receive a single response (instead of a stream of data), as you can then use more simple async-await structures. I've also added strong type definitions observerved from the responses

7572c4c - This implements the async-await syntax, and adds an extra method to delete the uploaded file if both steps of the conversion not fully successful (e.g. if an xls file has errors and can't be converted we won't store, so that a user can upload another version)

I also saw then note you made about using storage object ids. A good idea which I had previously tried using, although the challenge is supabase doesn't currently let you set the object id manually so it makes it impossible to import/export data as any time you create a new db all the storage object ids change and any tables referring to them break. So instead I just stored the bucket and folder names as variables to make it easier to retrieve the storage object path and populate as required.

But overall really nice work, there's still a few tasks we'll want to do as a follow-up (e.g. create new form entries, preview the form), I'll plan to create issue for those shortly and happy to merge here for now.