[services][refactoring] Tunnelbroker - Remove unique pointers from CryptoTools.

Summary:
We are aware of memory leaks using the new allocation for the cryptoPP classes and used unique pointers and release().
According to the CryptoPP pipeline documentation, we don't need to free the memory manually and can switch to the new approach because using unique pointers and release() have no makes sense here.

Related linear task: ENG-627

Test Plan: Successfully built the server and verify the string by the rsaVerifyString function.

Reviewers: karol-bisztyga, palys-swm, ashoat, jimpo

Reviewed By: palys-swm, ashoat

Subscribers: benschac, ashoat, palys-swm, Adrian, atul, karol-bisztyga

Differential Revision: https://phabricator.ashoat.com/D3186