Fixes #621

Problem:
GTM Pools  endpoint was missing from the SDK. This is the last of a series of PRs meant to introduce the GTM pools to the SDK

Analysis:
GTM pools were added with tests

Tests:
Flake8
Functional Tests
Unit Tests

Files Added/Changed:

f5-common-python/f5/bigip/tm/gtm/init.py
f5-common-python/f5/bigip/tm/gtm/pool.py
f5-common-python/f5/bigip/tm/gtm/test/test_pool.py
f5-common-python/test/functional/tm/gtm/test_pool.py

Author: wojtek0806

f5/bigip/tm/gtm/__init__.py

@@ -30,6 +30,7 @@
 
 from f5.bigip.resource import OrganizingCollection
 from f5.bigip.tm.gtm.datacenter import Datacenters
+from f5.bigip.tm.gtm.pool import Pools
 from f5.bigip.tm.gtm.rule import Rules
 from f5.bigip.tm.gtm.server import Servers
 from f5.bigip.tm.gtm.wideip import Wideips
@@ -41,6 +42,7 @@ def __init__(self, tm):
         super(Gtm, self).__init__(tm)
         self._meta_data['allowed_lazy_attributes'] = [
             Datacenters,
+            Pools,
             Rules,
             Servers,
             Wideips,