`odo dev` needs to handle changes in `devfile.yaml`

[kadel]

/kind user-story

User Story

• As an odo user
• I don't want to keep manually restarting odo dev command every time I edit something in devfile (like commandLine or env variable)
• it is annoying, time-consuming (for example in java-springboot stopping odo dev deletes m2 volume that serves as maven cache, next time everything needs to be downloaded again)

Acceptance Criteria

• [ ] odo dev should be able to handle changes in devfile.yaml
• [ ] when possible it should just update resources and let Kubernetes handle changes (re-deploy)
• [ ] things that were not updated should not be touched (example: editing env variable should not effect volumes)

/kind user-story

[rm3l]

Could be easier to implement with @feloy 's POC using controller-runtime: https://github.com/feloy/odo-dev-controller-poc

[feloy]

After some tests, I can see that odo dev is able to

• update the deployment when the container information is updated in the Devfile.
• deploy/undeploy Kubernetes components (including service bindings) to/from cluster when added/removed to/from the devfile

The first thing to fix would be to restart the port forwardings, which are lost after a pod restart

[feloy]

odo dev is not able to handle a change in Devfile if a Pod is not in a Running state. The consequence is that if the user starts odo dev with a "failing" Devfile or if it edits the Devfile to make it "fail" (env var makging the app fail, bad memory/cpu allocation, wrong command, etc), it needs to stop odo dev.

[valaparthvi]

@feloy It seems like we've covered all the ACs in this epic, I am not sure about the last one though. Please close this epic if you think we're good to go.