[services] Tunnelbroker - Move tools to the scope.

Summary:
Our 'tools' functions now reside in Tools.h,.cpp as a global scope which is not a good practice and will lead to functions confusion. The Tools functions must reside in their own tools namespace scope.

Linear task: ENG-958

Test Plan: Successfully built and run service using yarn run-tunnelbroker-service.

Reviewers: karol-bisztyga, palys-swm, varun

Reviewed By: palys-swm

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

Differential Revision: https://phabricator.ashoat.com/D3581