Add filter for network ls to hide predefined net

Add filter support for `network ls` to hide predefined network,
then user can use "docker network rm `docker network ls -f type=custom`"
to delete a bundle of userdefined networks.

Signed-off-by: Zhang Wei <zhangwei555@huawei.com>
Upstream-commit: 26dd026bd70c9c18a16b0e339821c309e56d8ff0
Component: engine

components/engine/docs/reference/api/docker_remote_api.md

@@ -109,6 +109,7 @@ This section lists each version from latest to oldest.  Each listing includes a
   the push or pull completes.
 * `POST /containers/create` now allows you to set a read/write rate limit for a 
   device (in bytes per second or IO per second).
+* `GET /networks` now supports filtering by `name`, `id` and `type`.
 
 ### v1.21 API changes
 

components/engine/docs/reference/api/docker_remote_api_v1.22.md

@@ -2728,7 +2728,7 @@ Status Codes
 
 **Example request**:
 
-    GET /networks HTTP/1.1
+    GET /networks?filters={"type":{"custom":true}} HTTP/1.1
 
 **Example response**:
 
@@ -2794,11 +2794,12 @@ Content-Type: application/json
 ]
 ```
 
-
-
 Query Parameters:
 
-- **filters** - JSON encoded value of the filters (a `map[string][]string`) to process on the networks list. Available filters: `name=[network-names]` , `id=[network-ids]`
+- **filters** - JSON encoded network list filter. The filter value is one of: 
+  -   `name=<network-name>` Matches all or part of a network name.
+  -   `id=<network-id>` Matches all or part of a network id.
+  -   `type=["custom"|"builtin"]` Filters networks by type. The `custom` keyword returns all user-defined networks.
 
 Status Codes: