App Script Error Checking

### Dependency
- #43

### Overview
We need an error checking process so that we can identify the causes and timely fixes.

### Details
During the automated onboarding process, there are several places where an error could occur which would result in a failure of the automation process. For example, an API call to Google or GitHub could fail for some unexplained reason which would result in the script failing. A user may also input an invalid email or GitHub handle which could cause a failure. It has been suggested that we implement some kind of error log that could be accessed by admins so that errors in the automation process can be remedied.

### Action Items
- [ ] Determine where in the automation process errors are likely to occur.
- [ ] Write basic error checking in the app scripts for the above places.
- [ ] Come up with a solution for error checking that is able to notify admins of these errors.

### Resources/Instructions
- Add more instructions on where in the code there could be errors.
- The initial idea for the error log is that they could potentially open up a new GitHub issue that admins are able to view during onboarding meetings, and can help new Hack for LA members during the onboarding sessions if there are any issues.