Improve VPNGatewaySelector tests coverage.

Add +13 and +14 timezones support.
Refactor & add tests for eipconfig
Merge remote-tracking branch 'ivan/feature/improve_eipconfig_tests' into develop
Merge remote-tracking branch 'ivan/feature/improve_vpngatewayselector_tests' into develop
Improve fake_provider to support the modified-if-needed feature
Fix problem with an SRPRegister test
Add missing openvpn.pem certificate for tests
Fix minor bugs and return defer in the run_* methods
Add ProviderBootstrapper tests