Add an option to publish service entries without a namespace by
specifying `-without-namespace=true`.

This commit also changes the behavior to not append namespace for
hostnames specified on ingress resources. The hostnames specified on
the resource will be advertised as-is.

Resolves #1

Signed-off-by: Renan Rodrigues <renanqts@gmail.com>

Co-authored-by: Blake Covarrubias <blake@covarrubi.as>