4.5.0 policy-handler - multi change

DCAEGEN2-853:
- stop reporting the absence of policies or updates
  as error - this is an expected result == INFO or WARNING

DCAEGEN2-903: preparation for TLS on the web-server of policy-handler

DCAEGEN2-930:
- configurable timeouts for http requests from policy-handler
- added configurable pinging on the web-socket to PDP
- added healthcheck info on the web-socket
- upgraded websocket-client lib to 0.53.0

DCAEGEN2-1017: fixed a bug on policy-filter matching
  by filter_config_name

- refactored and enhanced the unit-tests

Change-Id: I111ddc57bb978554ef376cbf916965b6667dad9b
Signed-off-by: Alex Shatov <alexs@att.com>
Issue-ID: DCAEGEN2-853
Issue-ID: DCAEGEN2-903
Issue-ID: DCAEGEN2-930
Issue-ID: DCAEGEN2-1017
diff --git a/requirements.txt b/requirements.txt
index df9b56d..632dfe5 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
 CherryPy>=15.0.0,<16.0.0
 psutil>=5.4.5,<6.0.0
 requests>=2.18.4,<3.0.0
-websocket-client==0.49.0
+websocket-client==0.53.0