feat(proxy_server.py): enable custom branding + routes on openapi docs

Allows user to add their branding + show only openai routes on docs

litellm/proxy/auth/litellm_license.py

@@ -0,0 +1,42 @@
+# What is this?
+## If litellm license in env, checks if it's valid
+import os
+from litellm.llms.custom_httpx.http_handler import HTTPHandler
+
+
+class LicenseCheck:
+    """
+    - Check if license in env
+    - Returns if license is valid
+    """
+
+    base_url = "https://license.litellm.ai"
+
+    def __init__(self) -> None:
+        self.license_str = os.getenv("LITELLM_LICENSE", None)
+        self.http_handler = HTTPHandler()
+
+    def _verify(self, license_str: str) -> bool:
+        url = "{}/verify_license/{}".format(self.base_url, license_str)
+
+        try:  # don't impact user, if call fails
+            response = self.http_handler.get(url=url)
+
+            response.raise_for_status()
+
+            response_json = response.json()
+
+            premium = response_json["valid"]
+
+            assert isinstance(premium, bool)
+
+            return premium
+        except Exception as e:
+            return False
+
+    def is_premium(self) -> bool:
+        if self.license_str is None:
+            return False
+        elif self._verify(license_str=self.license_str):
+            return True
+        return False