feat: implement ftl box run

[alecthomas]

This required some changes to how the build engine works, in that build and deploy can now be run separately.

Building the box:

🐚 ~/dev/ftl $ ftl box echo examples/go
info:time: Building module
info:echo: Building module
info: Building image echo

Running locally:

🐚 ~/dev/ftl $ ftl box-run --dsn="postgres://postgres:secret@localhost:15432/ftl?sslmode=disable" examples/go/
info: Web console available at: http://0.0.0.0:8892
info: HTTP ingress server listening on: http://0.0.0.0:8891
info:time: Deploying module
info: Reusing deployment: dpl-time-xpun6vddce07f5s
info: Deployed dpl-echo-1bd1tvnmig06767u
info: Deployed dpl-time-xpun6vddce07f5s
info:echo: Deploying module
info: Reusing deployment: dpl-echo-1bd1tvnmig06767u
info: All modules deployed

Running the resulting image works but we need to set up Docker compose with PG:

🐚 ~/dev/ftl $ docker run --platform linux/amd64 echo
ftl: error: failed to create database: database not ready after 10 tries: failed to connect to `user=postgres database=`:
             127.0.0.1:5432 (localhost): dial error: dial tcp 127.0.0.1:5432: connect: connection refused
             [::1]:5432 (localhost): dial error: dial tcp [::1]:5432: connect: connection refused