refactor: remove guzzlehttp/guzzle & ramsey/uuid

[jmtt89]

With these changes, the need for future maintenance of the library should be reduced.

• Remove guzzlehttp/guzzle and add custom CURL implementation for http request
• Remove ramsey/uuid for random_compat in >= php7 and use paragonie/random_compat polyfill for random_bytes() in PHP 5.x