added osu lazer setup script

src/setup/apps/osu_lazer.py

@@ -0,0 +1,15 @@
+from os.path import exists
+
+from src.util import flatpak_install, paru_install
+from src.setup.system import system76_scheduler
+
+name = "osu!lazer"
+
+
+def setup():
+    """
+    A circle-clicking rhythm game.
+    """
+
+    flatpak_install("sh.ppy.osu")
+    system76_scheduler.setup()