[Spike] Review documentation for event bindings on devfile.io and devfile schema

[thepetk]

/area documentation

Which area is this documentation change related to?

/area library

Issue details

It would be nice to review once more the event bindings page (https://devfile.io/docs/2.2.2/adding-event-bindings) on devfile.io. We could make more explicit any validation rules that the preStart & postStart fields have etc.

Other than the documentation at devfile.io we could also review the related fields on the devfile schema as they're might be implementation specific.

What mistake did you find / what is missing in the documentation?

N/A just a suggestion for improvement.

Acceptance Criteria

• [ ] The https://devfile.io/docs/2.2.2/adding-event-bindings has been reviewed and it explicitly mentions any rules regarding the postStart / preStart fields.
• [ ] The devfile schema description has been updated in order not to be impletantion specific for devworkspaces.

[Jdubrick]

If there is a change to documentation we need to ensure we test it out to make sure everything is okay