Swap MethodView for View in builder.static_from

Static views created with `static_from` had no metadata in the OpenAPI
representation.  This is fixed by subclassing our custom View.
There was a circular import problem, which I
have fixed by removing the `import builder` from `__init__.py`
This wasn't used, and only appeared in `__all__`.
It appears that removing the import has changed nothing;
`from labthings.views import *` still imports the `builder` module.

Author: rwb27

src/labthings/views/__init__.py

@@ -18,7 +18,6 @@
     build_action_schema,
 )
 from ..utilities import unpack
-from . import builder, op
 
 __all__ = ["MethodView", "View", "ActionView", "PropertyView", "op", "builder"]
 

src/labthings/views/builder.py

@@ -4,10 +4,10 @@
 from typing import Type
 
 from flask import abort, send_file
-from flask.views import MethodView
+from . import View
 
 
-def static_from(static_folder: str, name=None) -> Type[MethodView]:
+def static_from(static_folder: str, name=None) -> Type[View]:
     """
     :param static_folder: str:
     :param name:  (Default value = None)
@@ -37,6 +37,6 @@ def _get(_, path=""):
             return send_file(indexes[0])
 
     # Generate a basic property class
-    generated_class = type(name, (MethodView, object), {"get": _get})
+    generated_class = type(name, (View, object), {"get": _get})
 
     return generated_class