create-tap: improve code readability
create-tap: improve code readability

Add a struct that allows creating the tap device in 2 steps:
  - get the selinux labels and build the `exec.Command(...)`
  - selinux label handling and executing the tap making command

Signed-off-by: Miguel Duarte Barroso <c798d3f0e4fda7badfc3bbd91babde7ebd48b6c2@redhat.com>

kubevirt/kubevirt,davidvossel/kubevirt,kubevirt/kubevirt,stu-gott/kubevirt,kubevirt/kubevirt,kubevirt/kubevirt,davidvossel/kubevirt,stu-gott/kubevirt,davidvossel/kubevirt,stu-gott/kubevirt,stu-gott/kubevirt,davidvossel/kubevirt