Revert "Fix remote already exists error."

This reverts commit cf07af653a85416ae85c9496cd6591885066521d.
Fixed netinstall submodule error.
Set submodules to use HTTPS and added GitExtensionsSrc submodule to setupPush script.
Make SetupSrcrepos script add upstream remote when pulling the GitExtensionsSrc submodule and fetch the upstream objects.