feat: adapt to v1

[null8626]

The following pull request is a toned down version of #29 and a continuation of #30. This pull request focuses on the changes done to the SDK in the v1 of the API. Such as:

• Rewriting README.md (I could split this into another pull request if you want.)
• Changing the library's description to reflect the change on the C++ SDK (enforcing that it's community-maintained.)
• Renaming BotReviews to Reviews in case the API supports retrieving review information for other projects in the future.
• Adding a V1Client class with implementations of the new v1 endpoints that "extends" over Client via Rust's Deref.
• Adding widgets.
• Adding a Bearer prefix to the Authentication header.

This branch is already tested and linted (via cargo c, cargo clippy, and cargo doc --no-deps.)

[null8626]

Put on draft, will reopen once #32 is merged.