Update examples

[yanchuk]

have Examples like in NodeJS

• Atomic files https://github.com/mailtrap/mailtrap-nodejs/tree/main/examples/sending
• vs not atomic (all examples in one file) e.g. in PHP https://github.com/railsware/mailtrap-php/blob/main/examples/sending/emails.php

pros:

• easier to read
• We can link functionality to example files (merge that into one list)
• We show best-case scenarios of which functionality to use
• better for LLMs