Drop os-ken dependency

* Switch to python-docker library to start containers
* Switch to FRR image
* Improve bgp output parsing by using json
* Allow to run tests on multinode environment.
* Allow to run tests from tesmest running in container.
* Move base tests to ipv4 tests.

Related-Prod: PRODX-31417
Change-Id: Ic78a3b5d092aa9a6fd8343a856ef188dafe70b49
diff --git a/requirements.txt b/requirements.txt
index 21f14cc..00f6a90 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,7 +6,6 @@
 neutron-lib>=1.25.0 # Apache-2.0
 oslo.config>=5.2.0 # Apache-2.0
 netaddr>=0.7.18 # BSD
-os-ken>=0.3.0 # Apache-2.0
 oslo.log>=3.36.0 # Apache-2.0
 oslo.serialization!=2.19.1,>=2.18.0 # Apache-2.0
 oslo.utils>=3.33.0 # Apache-2.0
@@ -19,3 +18,4 @@
 testscenarios>=0.4 # Apache-2.0/BSD
 eventlet!=0.18.3,!=0.20.1,>=0.18.2 # MIT
 debtcollector>=1.2.0 # Apache-2.0
+docker  # Apache-2.0