5.1.0 policy-handler - policy-updates from new PDP

DCAEGEN2-1851:
- policy-handler now supports the policy-update notification
  from the new policy-engine thru DMaaP MR
  = no policy-filters - only policy-id values
- see README for discoverable config settings of dmaap_mr client
  = DMaaP MR client has the same flexibility as policy_engine
  = set the query.timeout to high value like 15000 (default)
- requests to DMaaP MR go through a single blocking connection
- first catch-up only after draining the policy-updates from DMaaP MR
  on the first loop
- safe parsing of messages from DMaaP MR
- policy-engine changed the data type for policy-version field
  from int to string that is expected to have the semver value
- related change to deployment-handler (DCAEGEN2-2085) has to be
  deployed to handle the non-numeric policyVersion
- on new PDP API: http /policy_latest and policy-updates
  return the new data from the new PDP API with the following fields
  added/renamed by the policy-handler to keep other policy related parts
  intact in R4-R6 (see pdp_api/policy_utils.py)
  * policyName = policy_id + "." + policyVersion.replace(".","-")
                                 + ".xml"
  * policyVersion = str(metadata["policy-version"])
  * "config" - is the renamed "properties" from the new PDP API response
- enabled the /catch_up and the periodic auto-catch-up for the new PDP
  API
- enabled GET /policies_latest - returns the latest policies for the
  deployed components
- POST /policies_latest - still disabled since no support for the
  policy-filters is provided for the new PDP API
- fixed hiding the Authorization value on comparing the configs
- logging of secrets is now sha256 to see whether they changed
- added X-ONAP-RequestID to headers the same way as X-ECOMP-RequestID
- on policy-update process the removal first, then addition
- changed the pool_connections=1 (number of pools) on PDP and DH sides
  == only a single destination is expected for each
- log the exception as fatal into error.log
- other minor fixes and refactoring
- unit-test coverage 74%
- integration testing is requested

DCAEGEN2-1976:
- policy-handler is enhanced to get user/password from env vars
  for PDP and DMaaP MR clients and overwriting the Authorization field
  in https headers received from the discoverable config
  = to override the Authorization value on policy_engine,
    set the environment vars $PDP_USER and $PDP_PWD in policy-handler
    container
  = to override the Authorization value on dmaap_mr,
    if using https and user-password authentication,
    set the environment vars $DMAAP_MR_USER and $DMAAP_MR_PWD in
    policy-handler container

Change-Id: Iad8eab9e20e615a0e0d2822f4735dc64c50aa55c
Signed-off-by: Alex Shatov <alexs@att.com>
Issue-ID: DCAEGEN2-1851
Issue-ID: DCAEGEN2-1976
diff --git a/LICENSE.txt b/LICENSE.txt
index c6c6e24..80a0d71 100644
--- a/LICENSE.txt
+++ b/LICENSE.txt
@@ -1,7 +1,7 @@
 /*
 * ============LICENSE_START==========================================
 * ===================================================================
-* Copyright (c) 2017-2019 AT&T Intellectual Property. All rights reserved.
+* Copyright (c) 2017-2020 AT&T Intellectual Property. All rights reserved.
 * ===================================================================
 *
 * Unless otherwise specified, all software contained herein is licensed