[Local] Allow disabling port publishing on host network

[TomerShor]

Currently we do not have an option for local (docker) environments to disable publishing the function container port on the host network. The only options are to select a specific port or a a random port.
This can cause possible security issues for users who do not want to expose their function on external URLs.

In this PR I've added to option to avoid publishing the function on the host network using the trigger attributes, which can be set in the function spec as follows:

spec:
  triggers:
    http-trigger:
      attributes:
        disablePortPublishing: true

Until this feature will be enabled in the GUI as well, this can also be set via trigger annotations, with the followin annotation:

"nuclio.io/disable-port-publishing": "true"

Note - this is already supported in a Kubernetes environment.

Resolves #2468

[rokatyy]

Just one question regarding implementation. Annotation part looks good to me.
Also - maybe it is worth covering this in our docs? (For instance, here)

[TomerShor]

@rokatyy Yes, once we go on a specific way to set it up I'll add it do the docs, not development docs but rather function configuration docs.
But PR is still a draft 😉

[rokatyy]

Looks great!
Just 2 minor suggestion :)