RouteOperator idempotency

[alacuku]

Description

This PR introduces a new way to manage the iptables rules for a remote peering cluster.
There are four general iptables chains:

• LIQO-POSTROUTING
• LIQO-PREROUTING
• LIQO-FORWARD
• LIQO-INPUT

for each peering cluster we create a postrouting, prerouting, forward and input chain. After each chain has been populated by rules based on the network parameters a reference for each of them is added to the general iptables chains.

All the methods used to manages the iptables rules and routes are idempotent. If some network parameters for peering cluster such as GatewayIP, PodCIDR change then the iptables rules and routes are updated accordingly to ensure the network connection with the peering cluster.

Fixes #257

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also note any relevant details for your test configuration.
unit tests

[coveralls]

Pull Request Test Coverage Report for Build 269194716

• 180 of 458 (39.3%) changed or added relevant lines in 4 files are covered.
• 132 unchanged lines in 7 files lost coverage.
• Overall coverage decreased (-1.7%) to 49.919%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/liqonet/route_mock.go	0	1	0.0%
pkg/liqonet/route.go	0	2	0.0%
internal/liqonet/route-operator.go	178	453	39.29%

Files with Coverage Reduction	New Missed Lines	%
internal/kubernetes/endpoints.go	4	76.33%
pkg/liqonet/route.go	6	0%
pkg/liqonet/iptables_mock.go	8	70.1%
internal/kubernetes/pod.go	12	9.21%
internal/liqonet/route-operator-config.go	13	0%
pkg/liqonet/route_mock.go	27	0%
internal/liqonet/route-operator.go	62	37.74%

Totals
Change from base Build 268911018:	-1.7%
Covered Lines:	6778
Relevant Lines:	13578

---

💛 - Coveralls

[palexster]

/rebase

[adamjensenbot]

Rebase status: success!