feat: adapt to v1

[null8626]

The following pull request does the following:

• Adapts the C++ SDK to v0 and v1 by adding features such as reviews and removing many legacy features. (Note that the search feature in GET /bots which will be removed in v1 as per Veld, is also removed.)
• Adds test files for testing the library. (see test.cpp and test_autoposter.cpp.)
• Makes the documentation more clear.
• Updates LICENSE copyright year.

As of v0, everything has been tested.

[null8626]

Hai everyone! At last we have a good news -- the SDK is now ready alongside v1! ❤️

[velddev]

Please lower the scope of your PR. You are changing too much in one PR to properly assess whether the changes are targeted to what they are.

[null8626]

Noted, thanks.

[null8626]

This pull request will be split into 4 pull requests:

1. The one that fixes/updates the v0 endpoints (feat: adapt to newer changes of v0 #13.)
2. The one that adds webhooks (feat: add webhooks support for cpp-httplib and drogon  #15.)
3. The one that adds v1 endpoints (TBA.)
4. The one that adds tests (TBA.).