rename package (_rus suffix), convert to pyproject.toml, poetry lints

test.py

@@ -1,4 +1,4 @@
-from prometheus import Path, Counter, Gauge, Summary, GLOBAL_REGISTRY, NOW
+from prometheus_rus import Path, Counter, Gauge, Summary, GLOBAL_REGISTRY, NOW
 
 g1 = Gauge(value=20, path=Path("foobar_g1", {"server": "[host:xy]"}), help="foo help with bar")
 g2 = Gauge(path=Path("foobar_g2", {"server": "[host:xy]"}), help="foo help with bar")