Add ability to limit amount uploaded by a user (#18527)

You can now configure how much media can be uploaded by a user in a
given time period.

Note the first commit here is a refactor of create/upload content
function

schema/synapse-config.schema.yaml

@@ -2335,6 +2335,30 @@ properties:
     default: 50M
     examples:
       - 60M
+  media_upload_limits:
+    type: array
+    description: >-
+      A list of media upload limits defining how much data a given user can
+      upload in a given time period.
+
+
+      An empty list means no limits are applied.
+    default: []
+    items:
+      time_period:
+        type: "#/$defs/duration"
+        description: >-
+          The time period over which the limit applies. Required.
+      max_size:
+        type: "#/$defs/bytes"
+        description: >-
+          Amount of data that can be uploaded in the time period by the user.
+          Required.
+    examples:
+      - - time_period: 1h
+          max_size: 100M
+        - time_period: 1w
+          max_size: 500M
   max_image_pixels:
     $ref: "#/$defs/bytes"
     description: Maximum number of pixels that will be thumbnailed.