SELinux: Add dedicated policy for ipa-pki-retrieve-key
    
    Add proper labeling, transition and policy for ipa-pki-retrieve-key.
    Make sure tomcat_t can execute ipa-pki-retrieve-key.
    
    Fixes: https://pagure.io/freeipa/issue/8488
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Signed-off-by: François Cami <fcami@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
    Reviewed-By: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>
    Reviewed-By: Ondrej Mosnacek <omosnace@redhat.com>
    Reviewed-By: Lukas Vrabec <lvrabec@redhat.com>
    Reviewed-By: Zdenek Pytela <zpytela@redhat.com>
    Reviewed-By: Thomas Woerner <twoerner@redhat.com>