Add telemetry support for usage analysis

[ekerfelt]

Enables support for collecting usage telemetry and adding CLI commands and ENV vars for enabling/disabling telemetry

$ encoredev telemetry -h
Reports the current telemetry status

Usage:
  encore telemetry [flags]
  encore telemetry [command]

Available Commands:
  disable     Disables telemetry reporting
  enable      Enables telemetry reporting

Flags:
  -h, --help   help for telemetry

Global Flags:
      --trace string    file to write execution trace data to
  -v, --verbose count   verbose output

Use "encore telemetry [command] --help" for more information about a command.

[encore-cla]

All committers have signed the CLA.