* adds start as default subcommand for zebrad
* moves EntryPoint to submodule and adds a test
* moves all start tests to config_test to avoid listener conflicts
* Update zebrad/src/application/entry_point.rs docs
* Revert "moves all start tests to config_test to avoid listener conflicts"
This reverts commit 61ce46f5a1.
* Update based on test API changes from another PR
Co-authored-by: teor <teor@riseup.net>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>