solve #610
convert service.pid to Pod.Spec.HostPid
set Pod.Spec.HostPid to true if service.pid ="host", to false otherwise
update conversion.md on support for the key
This commit Add support for cap_add & cap_drop which maps to
Pod.Spec.Container.SecurityContext.Capabilities.Add/Drop
Added unit tests for ConfigCapabilities function
Updated conversion.md on support for these keys