by_json: Generate circulation policies

* Generate a new circulation policies file: policies.svg
  * Parses Circulation policies
  * Parses Item Types

by_json/filters/circulation_policies

@@ -0,0 +1,12 @@
+.[] | {
+  pid,
+  name,
+  description,
+  organisation: .organisation."$ref",
+  allow_checkout,
+  checkout_duration,
+  allow_requests,
+  policy_library_level,
+  libraries: [.libraries[]?],
+  settings
+}

by_json/filters/item_types

@@ -0,0 +1,6 @@
+.[] | {
+  pid,
+  name,
+  organisation: .organisation."$ref",
+  type
+}