wait for tunnels to be ready (take 2)

[royra]

• CTA: add state prop to /tunnels API endpoint. checks that all compose services have been started by docker, and that all potential tunnels for these services have been started by the CTA.
• CLI: check new prop in up and urls commands. can be disabled with the --no-wait flag

Compatible with compose services which have no ports, e.g, one-off services such as DB init. Supersedes #479 which is not compatible with such services.