[native] Add wrapper functions for getting and setting device id in cpp

Summary: We need to be able to call getting and setting device id from cpp. In D5316 it has been decided (by setting setMetadata etc. functions to be private) that we'll have wrapper functions for all metadata entries to keep the code clean.

Test Plan:
Add in AppDelegate.mm to didFinishLaunchingWithOptions the following lines:

comm::DatabaseManager::getQueryExecutor().setDeviceID(":)))))");
comm::Logger::log(comm::DatabaseManager::getQueryExecutor().getDeviceID());

And see that ":)))))" gets logged to the console. I also checked by setting breakpoints before and after these lines that in the SQLite Metadata table for the simulator there appears device_id entry with :))))) in the data column.

Reviewers: marcin, michal, jon, tomek

Reviewed By: marcin, tomek

Subscribers: ashoat, tomek, atul, abosh

Differential Revision: https://phab.comm.dev/D5339