TypeScript implementation

[whyboris]

This is a sample start on what a TypeScript implementation would look like.

Discussion: #46

The key benefit of TypeScript here is strict typing of method arguments.

Other changes:

• using opn instead of open (deprecated)
• simpler export
• minor version bumps

⚠️ THIS IS NOT READY TO MERGE ⚠️

If TypeScript were to be implemented, the release procedures would need to change somewhat (it's the built files that need to be a part of the CLI, not the original TypeScript files).

If idea is approved, before release I would:

• add JSDoc
• add more strong typing of variables
• clean up scripts (e.g. yarn test would run yarn build first)
• figure out how to make the exported package still work 😅

[rtfpessoa]

@whyboris looks good. I need to get some time to test it.

[whyboris]

No rush -- and I'm happy to work more on this -- let me know if you have any recommended direction (especially if different than what I've done) 👍

[rtfpessoa]

@whyboris noticed some changes required:

• Change the main in package.json to the built one
• Change src from the published libraries to built

and overall I would prefer to move all files to TS and enable a couple more settings in the end to enforce types and best practices.

[rtfpessoa]

@whyboris noticed some changes required:

• Change the main in package.json to the built one
• Change src from the published libraries to built
• Change the binary inside bin to point to built directory also

and overall I would prefer to move all files to TS and enable a couple more settings in the end to enforce types and best practices.

[whyboris]

Sorry I dropped out after I opened this PR 😅 was a bit busy 😄
I'll likely find some time in the next month to address your recommendations 👍

[rtfpessoa]

Closing for #53