Pick a shorthand switch for logging (-v is already taken for variables)

[stuartpa]

A typical support scenario is going to be, can you run that command again with full logging, e.g.

sqlcmd create mssql -v 4

Which is currently short for

sqlcmd create mssql --verbosity 4

But:

-v is taken, -l is taken.

What's the POSIX CLI norm for getting full logging? (is --verbosity even a good flag name for this)

[stuartpa]

I've noticed most golang based COBRA clis using --debug (for what we currently use --verbosity 4 for),