feat: Use determinate systems nix installer

Fixes #209

Author: KyleGospo

system_files/deck/shared/usr/share/ublue-os/just/custom.just

@@ -54,7 +54,7 @@ get-steamcmd:
   rm /tmp/steamcmd.tar.gz
 
 install-nix:
-  curl -s https://raw.githubusercontent.com/dnkmmr69420/nix-installer-scripts/main/installer-scripts/silverblue-nix-installer.sh | bash
+  curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install
 
 remove-nix:
   curl -s https://raw.githubusercontent.com/dnkmmr69420/nix-installer-scripts/main/uninstaller-scripts/silverblue-nix-uninstaller.sh | bash

system_files/desktop/shared/usr/share/ublue-os/just/custom.just

@@ -42,7 +42,7 @@ install-corectrl:
   rpm-ostree kargs --append="amdgpu.ppfeaturemask=0xffffffff"
 
 install-nix:
-  curl -s https://raw.githubusercontent.com/dnkmmr69420/nix-installer-scripts/main/installer-scripts/silverblue-nix-installer.sh | sudo bash
+  curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install
 
 remove-nix:
   curl -s https://raw.githubusercontent.com/dnkmmr69420/nix-installer-scripts/main/uninstaller-scripts/silverblue-nix-uninstaller.sh | sudo bash