Odo should use apply command for preStart(and postStop when its implemented)

[maysunfaisal]

There is a semantic difference between an exec and apply command - exec commands are to be executed only when a container is up and running and apply commands are applied when there is no running container.

However, odo only has exec and composite commands in its scope and preStart utilizes an exec command. But according to the schema definition and interpretation this is not right. See issue devfile/api#204 for discussion.

Currently no odo devfiles have a preStart, so it would be good to update the implementation to use apply commands before a devfile starts using it.

For more information on which events use apply/exec, pls read devfile validation doc - https://github.com/devfile/api/blob/master/pkg/validation/validation-rule.md. Also note the condition for composite commands when it comes to events!

cc: @kadel

[maysunfaisal]

@kadel @dharmit FYI, this issue will be need to be addressed when odo switches validation to devfile library and api as per #4361

There is currently an open PR to consolidate validations in devfile/api#301

[kadel]

odo currently doesn't support apply commands. This means that odo can't currently support preStart event.
A temporary solution until we have apply support in odo is not to support preStart event. So odo will error out in case of devfile with preStart