add initial implementation of auth gateway with models, routes, and session management

containers/auth-gateway/auth_gateway/models/applications.py

@@ -0,0 +1,20 @@
+from pydantic import BaseModel, Field
+
+
+class StaticRouteModel(BaseModel):
+    path_prefix: str
+    root: str
+    strip_prefix: str | None = None
+    cache_control: str | None = None
+
+
+class ApplicationModel(BaseModel):
+    id: str
+    name: str
+    hosts: list[str] = Field(default_factory=list)
+    upstream: str
+    static_routes: list[StaticRouteModel] = Field(default_factory=list)
+
+
+class ApplicationsFileModel(BaseModel):
+    entries: list[ApplicationModel] = Field(default_factory=list)