[PBH] Implement Edit Flows (sonic-net#2093)

PBH Edit Flows is a second phase of PBH feature implementation. It allows user to modify the already existing objects.
PBH Edit Flows offer a full entity update which assumes Config DB field ADD/UPDATE/REMOVE processing.

HLD: sonic-net/SONiC#909

- What I did
Implemented Edit Flows in scope of PBH enhancement

- How I did it
Implementation is done according to the PBH HLD

Signed-off-by: Nazarii Hnydyn <nazariig@nvidia.com>

clear/main.py

@@ -4,10 +4,10 @@
 import sys
 import click
 import utilities_common.cli as clicommon
-import json
 
 from utilities_common import util_base
 from show.plugins.pbh import read_pbh_counters
+from config.plugins.pbh import serialize_pbh_counters
 from . import plugins
 
 
@@ -473,14 +473,8 @@ def statistics(db):
     pbh_rules = db.cfgdb.get_table("PBH_RULE")
     pbh_counters = read_pbh_counters(pbh_rules)
 
-    try:
-        with open('/tmp/.pbh_counters.txt', 'w') as fp:
-            json.dump(remap_keys(pbh_counters), fp)
-    except IOError as err:
-        pass
+    serialize_pbh_counters(pbh_counters)
 
-def remap_keys(dict):
-    return [{'key': k, 'value': v} for k, v in dict.items()]
 
 # ("sonic-clear flowcnt-trap")
 @cli.command()