Desktop: Add Desktop app to Windows & Mac Stores

[jasonblais]

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Summary
Add Desktop app to Windows & Mac Stores

Need to think about how this would work for Enterprise customers running a private fork of the app.

[yuya-oc]

For Windows, we can use Desktop App Converter.

https://mspoweruser.com/slack-brings-desktop-app-windows-store/

[yuya-oc]

Guides for Mac App Store: https://electron.atom.io/docs/tutorial/mac-app-store-submission-guide/

[JacobDB]

I'd like to see this as well! Please make sure to include a "Windows 10-style" icon for the taskbar & start menu; I've attached one that I currently use in my taskbar.

Screenshot:

Icon (hard to see because it's white on white):

For the start menu tile, I'd recommend using #2397E2 as the background, the same blue you use on your website :)

[amyblais]

Jira ticket: https://mattermost.atlassian.net/browse/MM-14067

[MathiasMagnus]

I think the issue was a little too hastily closed, as the linked JIRA ticket has had no activity in the past 7 months. Indeed, a Microsoft Store version would be appreciated.