[services] Tunnelbroker - Validate sessionID and deviceID in database entities.

Summary:
Validating sessionID and deviceID fields in database item entities using validation functions in Tools.

Note:
Validating empty strings are moved to D3525 which will be merged.

Related linear task: ENG-618

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

Reviewers: palys-swm, karol-bisztyga, varun

Reviewed By: palys-swm

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

Differential Revision: https://phabricator.ashoat.com/D3526