Handle errors on create new timer

[luetkemj]

Description

• Throw useful errors in during timer parsing that are caught and displayed in the UI to help guide a user to enter a correct new timer formula.

Related Issue

• 5

Motivation and Context

• Previously the errors would create a red border around the input with no indication to the user exactly what was wrong or how to fix it. This work provides useful errors to the user so they can successfully add timers

Screenshots (if appropriate):

Types of changes

• What types of changes does your code introduce? Put an x in all the boxes that apply:
• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Style change (non-breaking change that adds no functionality or fixes an issue)

Checklist:

• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.
• [x] I have added a screenshot if appropriate.
• Tested in
• [x] Chrome
• [x] Safari
• [x] Firefox
• [ ] Edge