Start scheduler after X moment in time

[madflojo]

Description

This pull request adds the ability to tell the scheduler not to schedule a task until after X point in time. This is useful for when you want to schedule something to start in the future but not now. I.E. I want to start an email task every Sunday, I could start the scheduler by waiting X days until next Sunday and give the task an interval of 7 days.

Type of change

• New feature (non-breaking change which adds functionality)
• Small and simple changes (Tech Debt, Doc updates, Adding tests, etc.)

Checklist:

• I have performed a self-review of my own code
• I have commented my code, ensuring GoDoc readability and clarity in hard-to-understand areas
• I have made corresponding changes to documentation
• I have added tests that ensure my fix is effective or that my feature works
• Any dependent changes have been merged and published in downstream modules

If checklist items are unchecked please explain.

No downstream dependencies.