Disable console feature by default

The console feature allows users with the 'console' permission
to execute arbitrary JavaScript in the context of the server
process. This allows for the execution of arbitrary code on the
local computer running the Pokemon Showdown server. As such,
the console permission is different from all other permissions
in that it gives power over more than just Pokemon Showdown.

It is likely that most users do not realise how powerful the
console permission is. As such, this commit alters the 'root'
permission so that it does not include the 'console' permission.
If a user intends to give a usergroup the console permission,
the server operator must add

    console: true

to a usergroup's permissions in config.js.

This implementation also has the effect of disabling the
console feature on all current servers that pull this commit,
unless they explicitly enable it for a usergroup.

Please do not enable the console permission unless you fully
understand how powerful it is.