This PR makes a user visible behavior change with userland
proxy disabled by default and rely on hairpin NAT to be enabled
by default. This may not work in older (unsupported) kernels
where the user will be forced to enable userlandproxy if needed.
- Updated the Docs
- Changed the integration-cli to start with userlandproxy
desiabled by default.
Signed-off-by: Jana Radhakrishnan <mrjana@docker.com>