Quarks system should be able to work without installing Git

[cdbzb]

Motivation

Currently users are required to install Git to use Quarks - this can be challenging for new users who don't come form a coding background esp on Windows.

Description of Proposed Feature

on my system: curl -L -O https://github.com/supercollider-quarks/downloaded-quarks/archive/refs/heads/master.zip works.

Quarks should fall back to curl if Git is not installed