Lint the contrib/ directory in CI and linting scripts, add synctl to linting script (#7914)

Run `isort`, `flake8` and `black` over the `contrib/` directory and `synctl` script. The latter was already being done in CI, but now the linting script does it too.

Fixes https://github.com/matrix-org/synapse/issues/7910

contrib/cmdclient/console.py

@@ -17,9 +17,6 @@
 """ Starts a synapse client console. """
 from __future__ import print_function
 
-from twisted.internet import reactor, defer, threads
-from http import TwistedHttpClient
-
 import argparse
 import cmd
 import getpass
@@ -28,12 +25,14 @@ import shlex
 import sys
 import time
 import urllib
-import urlparse
+from http import TwistedHttpClient
 
-import nacl.signing
 import nacl.encoding
+import nacl.signing
+import urlparse
+from signedjson.sign import SignatureVerifyException, verify_signed_json
 
-from signedjson.sign import verify_signed_json, SignatureVerifyException
+from twisted.internet import defer, reactor, threads
 
 CONFIG_JSON = "cmdclient_config.json"
 
@@ -493,7 +492,7 @@ class SynapseCmd(cmd.Cmd):
         "list messages <roomid> from=END&to=START&limit=3"
         """
         args = self._parse(line, ["type", "roomid", "qp"])
-        if not "type" in args or not "roomid" in args:
+        if "type" not in args or "roomid" not in args:
             print("Must specify type and room ID.")
             return
         if args["type"] not in ["members", "messages"]:
@@ -508,7 +507,7 @@ class SynapseCmd(cmd.Cmd):
                 try:
                     key_value = key_value_str.split("=")
                     qp[key_value[0]] = key_value[1]
-                except:
+                except Exception:
                     print("Bad query param: %s" % key_value)
                     return
 
@@ -585,7 +584,7 @@ class SynapseCmd(cmd.Cmd):
                 parsed_url = urlparse.urlparse(args["path"])
                 qp.update(urlparse.parse_qs(parsed_url.query))
                 args["path"] = parsed_url.path
-            except:
+            except Exception:
                 pass
 
         reactor.callFromThread(
@@ -772,10 +771,10 @@ def main(server_url, identity_server_url, username, token, config_path):
             syn_cmd.config = json.load(config)
             try:
                 http_client.verbose = "on" == syn_cmd.config["verbose"]
-            except:
+            except Exception:
                 pass
             print("Loaded config from %s" % config_path)
-    except:
+    except Exception:
         pass
 
     # Twisted-specific: Runs the command processor in Twisted's event loop