Generic solution for accessing base information about steps / step results

[viktorbenei]

As noted here https://github.com/bitrise-io/steps-xcode-test/issues/8 it would be great to have a generic solution to get at least a Step's status from another Step. This could be used to send status information in web hooks or messages (email / Slack).

Would be good:

• get the first failed step's title/id (if any)
• get a specific step's result (success/failed/skipped/...)
• get a full step-results summary, similar to the summary printed at the end of a bitrise run