feat!: Client#post() always returns array of responses

[nzakas]

This pull request includes several changes to improve the handling of responses and type definitions in the src/bin.js and src/client.js files, as well as updates to the corresponding tests.

The Client#post() method previously threw an error when an API request failed, meaning you wouldn't get any info about requests that succeeded. This PR changes the behavior of Client#post() so that it always returns an array of responses, similar to Promise.allSettled(). This also allows you to register multiple different versions of the same strategy to post to.

Improvements to response handling:

• src/client.js: Added SuccessResponse and FailureResponse classes to represent successful and failed responses, respectively.
• src/client.js: Updated the post method in the Client class to return an array of SuccessResponse or FailureResponse objects instead of a mixed object.
• src/bin.js: Updated the handling of responses to use the new isSuccessResponse helper function and log results accordingly.

Improvements to type definitions:

• src/bin.js: Added type definitions and updated the options object to use a constant type for boolean values.
• src/bin.js: Added type annotations for the strategies array.

Updates to tests:

• tests/client.test.js: Updated tests to check for SuccessResponse and FailureResponse objects instead of mixed objects. [1] [2] [3]