Rename rust folder to sgl-router (#2464)

Signed-off-by: Ata Fatahi <immrata@gmail.com>

sgl-router/py_src/sglang_router/__init__.py

@@ -0,0 +1,11 @@
+# a lightweihgt wrapper on router with argument type and comments
+from sglang_router_rs import PolicyType
+
+# no wrapper on policy type => direct export
+from .router import Router
+
+__all__ = ["Router", "PolicyType"]
+
+from sglang_router.version import __version__
+
+__all__ += ["__version__"]