Support "online" stores for Prices

[monsieurtanuki]

Problem

Initially, there were only physical locations for Prices.
Recently, online stores (website url) were introduced, and we currently don't support that in Smoothie.

Proposed solution

Change the location management so that we can select online stores for prices.

[teolemon]

As far as new features from Open Prices go, I am unsure this is a priority one.
We have UX reports for the current one, and we have also new features from the web (a major one is a DEV Mode Gemini-based contribution assistant which is insanely good, but we need to figure out scalability).
I need to compile a list of changes from the Web Version.
cc @raphodn @raphael0202

[monsieurtanuki]

I'm not saying it's a priority: it's just that recent changes in Prices may make Smoothie partially incorrect / crash (go to "My proofs" / select a proof / add a price - what's supposed to be displayed now for the location if the proof location is online?).
For the record a related change was included in off-dart 3.18.0 published yesterday.

[teolemon]

For this one, related: are we displaying prices already related to the proof ? I have a feeling we're not, potentially leading to duplicate prices (readding prices from the proof screen)

[monsieurtanuki]

are we displaying prices already related to the proof ?

I don't think we are.