Added error handling and a job id PR comment for a new job

[nerdalert]

• Add error handling to status. The user gets a comment with details and the status alerts there was an error with the job id for correlation to the comment.
• Add an initial comment after a trigger for a pending job with the job type and job ID. The job ID lets the user and us operating the service easily correlate a job to results/logs for troubleshooting.
• Added a PullRequestStatusParams struct to encapsulate parameters to util.*
• Adjust status messages to be visible in the limited width window of the PR's status box.

Closes #170 Closes #199 Closes #186

[nerdalert]

@vishnoianil Here is output from the three functions. I just added one comment at trigger to give a job ID and job type so it's easy to correlate to the status box (and message to look in the status box for results). A couple of the status msgs don't quite fit but we can tinker with that later.

Here is output from an error (note: the error is reproducible just deleting the tax repo on the worker but is dependent on #207.

See what you think, ty!