Restructure tinytodo and tinytodo-go to avoid duplication

[mqf20]

Category

tinytodo

Describe the expansion you'd like to request

This is a follow-up of #182.

@shaobo-he-aws suggested (see comment and comment) to restructure tinytodo and tinytodo-go to reuse code and avoid duplication, since both examples share several files.

Also fix spelling error.

Additional context

No response

Is this something that you'd be interested in working on?

• 👋 I may be able to implement this feature request
• ⚠️ This feature might incur a breaking change