Separate vfolder deletion API

* Original delete (instance) method do not accept folder ID to keep the abstraction.
* vfolder deletion by folder ID will be performed by class method "delete_by_id".

Author: adrysn

src/ai/backend/client/vfolder.py

@@ -37,6 +37,14 @@ async def create(cls, name: str, host: str = None, group: str = None):
         async with rqst.fetch() as resp:
             return await resp.json()
 
+    @api_function
+    @classmethod
+    async def delete_by_id(cls, oid):
+        rqst = Request(cls.session, 'DELETE', '/folders')
+        rqst.set_json({'id': oid})
+        async with rqst.fetch():
+            return {}
+
     @api_function
     @classmethod
     async def list(cls, list_all=False):
@@ -73,10 +81,8 @@ async def info(self):
             return await resp.json()
 
     @api_function
-    async def delete(self, oid=None):
+    async def delete(self):
         rqst = Request(self.session, 'DELETE', '/folders/{0}'.format(self.name))
-        if oid is not None:
-            rqst.set_json({'id': oid})
         async with rqst.fetch():
             return {}