start.ShowMessage: remove the logrus INFO header, for ease of copypasting

[AkihiroSuda]

• Commit 1: start.ShowMessage: remove the logrus INFO header, for ease of copypasting
• Commit 2: examples/docker.yaml: recommend CLI context, not DOCKER_HOST env var

Example output:

$ limactl start ./examples/docker.yaml 
? Creating an instance "docker" Proceed with the default configuration
INFO[0001] Attempting to download the image from "https://cloud-images.ubuntu.com/impish/current/impish-server-cloudimg-amd64.img"  digest=
INFO[0002] Using cache "/Users/suda/Library/Caches/lima/download/by-url-sha256/ac74da77a6828e35de7edaa06fdbb33d12ef97cce2726550017e3c1066c88fb1/data" 
INFO[0003] [hostagent] Starting QEMU (hint: to watch the boot progress, see "/Users/suda/.lima/docker/serial.log") 
INFO[0003] SSH Local Port: 58833                        
INFO[0003] [hostagent] Waiting for the essential requirement 1 of 5: "ssh" 
INFO[0031] [hostagent] Waiting for the essential requirement 1 of 5: "ssh" 
INFO[0066] [hostagent] The essential requirement 1 of 5 is satisfied 
INFO[0066] [hostagent] Waiting for the essential requirement 2 of 5: "user session is ready for ssh" 
INFO[0066] [hostagent] The essential requirement 2 of 5 is satisfied 
INFO[0066] [hostagent] Waiting for the essential requirement 3 of 5: "sshfs binary to be installed" 
INFO[0066] [hostagent] The essential requirement 3 of 5 is satisfied 
INFO[0066] [hostagent] Waiting for the essential requirement 4 of 5: "/etc/fuse.conf to contain \"user_allow_other\"" 
INFO[0069] [hostagent] The essential requirement 4 of 5 is satisfied 
INFO[0069] [hostagent] Waiting for the essential requirement 5 of 5: "the guest agent to be running" 
INFO[0069] [hostagent] The essential requirement 5 of 5 is satisfied 
INFO[0069] [hostagent] Mounting "/Users/suda"           
INFO[0070] [hostagent] Mounting "/tmp/lima"             
INFO[0070] [hostagent] Waiting for the optional requirement 1 of 1: "user probe 1/1" 
INFO[0070] [hostagent] Forwarding "/run/user/501/docker.sock" (guest) to "/Users/suda/.lima/docker/sock/docker.sock" (host) 
INFO[0070] [hostagent] Forwarding "/run/lima-guestagent.sock" (guest) to "/Users/suda/.lima/docker/ga.sock" (host) 
INFO[0070] [hostagent] Not forwarding TCP 127.0.0.53:53 
INFO[0070] [hostagent] Not forwarding TCP 0.0.0.0:22    
INFO[0070] [hostagent] Not forwarding TCP [::]:22       
INFO[0109] [hostagent] The optional requirement 1 of 1 is satisfied 
INFO[0109] [hostagent] Waiting for the final requirement 1 of 1: "boot scripts must have finished" 
INFO[0115] [hostagent] The final requirement 1 of 1 is satisfied 
INFO[0115] READY. Run `limactl shell docker` to open the shell. 
INFO[0115] Message from the instance "docker":          
To run `docker` on the host (assumes docker-cli is installed), run the following commands:
------
docker context create lima --docker "host=unix:///Users/suda/.lima/docker/sock/docker.sock"
docker context use lima
docker run hello-world
------

[afbjorklund]

I have no idea about this "docker context", but I prefer not messing up my global environment (outside the current shell)

The same goes for using "podman system connection", versus just using the CONTAINER_HOST environment variable...

[afbjorklund]

Making it easier to copy/paste sounds good, though :-)

[jandubois]

LGTM

I think showing how to set up a docker context is useful!

We could show the DOCKER_HOST variant as well, and let the user choose, but I think they can also figure it out themselves from the docker context example.