Add Squirrel installertype

[superusercode]

Description of the new feature/enhancement

This installertype is popular with many electron apps, including discord and authy. Using the "squirrel" installer type would automatically add the silent switches for installation like nullsoft and innosetup do.

---

Edited by @denelon - Related to:

• Support special behavior for upgrading Squirrel applications #1748
• Support installers that close the install process and launch a new process for install #418

[kayone]

This topic brings me a lot of sadness as someone that worked with MANY of different installer engines.

From client-side installation, management Squirrel was by far, the best, most predictable and easiest to parse and work with.

@superusercode, as you mentioned a lot of electron app, used Squirrel for their installers, but that is something that getting less and less common and most are moving to NSIS, which, unfortunately, one of the worst installer engines as far as parsing/and predictability.

what is the point of all this, well, I just wanted to say how much I love squirrel. and more people should be using it. also, it makes total sense to get added to WinGet.

[denelon]

This could be grouped with #360

[mimi89999]

The big problem with Squirrel installers is that only user installs are supported. Machine wide installations are not.
Admins using winget would be very surprised if after installing an app it was only installed on their account.
I don't see how Squirrel installers can be supported in winget.

[felipecrs]

By the way, what should be the correct flags to add in a squirrel installer when adding to winget-pkgs?