ENYO-2090: replace console.log by npmlog & allow log to file

- replace '-v' option by `--level XXX` to use npmlog
- add `-L` option to active logging to a file `ide.log`
- update usage instructions accordingly, add bug reporting instructions

Enyo-DCO-1.1-Signed-off-by: Francois-Xavier KOWALSKI <francois-xavier.kowalski@hp.com>