Add a --log-local-time flag that configures cloudflared to use local
timezone for log timestamps instead of the default UTC.
This helps users correlate logs with local system events and other
services running in their timezone.
The flag can also be set via the TUNNEL_LOG_LOCAL_TIME environment
variable.
Closes#1530
## Summary
This commit refactors some of the flags of cloudflared to their own module, so that they can be used across the code without requiring to literal strings which are much more error prone.
Closes TUN-8914
Hugh
Devin Carr
João "Pisco" Fernandes