Simplified deploy/drain timeouts

Remove `stop_wait_time` and `readiness_timeout` from the root config
and remove `deploy_timeout` and `drain_timeout` from the proxy config.

Instead we'll just have `deploy_timeout` and `drain_timeout` in the
root config.

For roles that run the proxy, they are passed to the kamal-proxy deploy
command. Once that returns we can assume the container is ready to
shut down.

For other roles, we'll use the `deploy_timeout` when polling the
container to see if it is ready and the `drain_timeout` when stopping
the container.

test/fixtures/deploy_with_proxy.yml

@@ -13,8 +13,6 @@ registry:
 builder:
   arch: amd64
 
-proxy:
-  deploy_timeout: 6s
 
 accessories:
   mysql:
@@ -39,4 +37,4 @@ accessories:
       - data:/data
 
 readiness_delay: 0
-readiness_timeout: 1
+deploy_timeout: 6