[native] Add wrapper for generate_device_id

Summary: Add a wrapper function for generate_device_id, as suggested in comments on D5341.

Test Plan:
Insert the following to didFinishLaunchingWithOptions in AppDelegate.mm:

comm::Logger::log(comm::generateDeviceID("MOBILE"));

Run ios and see that when app launches a string subject to "^(ks|mobile|web):[a-zA-Z0-9]{64}$" is logged to the console

Reviewers: marcin, varun, jon, tomek

Reviewed By: marcin, varun, tomek

Subscribers: ashoat, tomek, atul, abosh

Differential Revision: https://phab.comm.dev/D5369