Sle16 libreswan approved tunnels

[teacup-on-rockingchair]

Description:

• Enable libreswan_approved_tunnels rule for sle16

Rationale:

• Adapt libreswan_approved_tunnels for sle16 and sle15
• Use checks and remediation instructions references with strongswan, as it is the default IPSec solution for sle15 and sle16 platforms
• set strongswan package is the libreswan alternative for sle15 and sle16
• Allocate CCE for sle16 support for libreswan_approved_tunnels rule

[openshift-ci]

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