Extension: add example extension (#644)

* add example ext files

* remove from extension list

lnbits/extensions/example/views.py

@@ -0,0 +1,18 @@
+from fastapi import FastAPI, Request
+from fastapi.params import Depends
+from fastapi.templating import Jinja2Templates
+from starlette.responses import HTMLResponse
+
+from lnbits.core.models import User
+from lnbits.decorators import check_user_exists
+
+from . import example_ext, example_renderer
+
+templates = Jinja2Templates(directory="templates")
+
+
+@example_ext.get("/", response_class=HTMLResponse)
+async def index(request: Request, user: User = Depends(check_user_exists)):
+    return example_renderer().TemplateResponse(
+        "example/index.html", {"request": request, "user": user.dict()}
+    )