Updating index-v1 repos does not send progress events

There is a TODO left in the index-v1 code, to do with sending out the relevant progress events.

Right now, if you update the F-Droid repo on 0.103.* then you will notice that it only ever says "Connecting to https://f-droid.org/..." for the entire duration of the repo update. The progress events which it needs are:

• Download progress
• Processing of apps
• "Saving application details" which happens after processing of apps is complete (while it is calculating preferred metadata, suggested versions, etc).