* lang/funcs: add (console-only) TypeFunction

The type() function, which is only available for terraform console,
prints out the type of a given value. This is mainly intended for
debugging - it's nice to be able to print out terraform's understanding
of a complex variable.

This introduces a new field for Scope: ConsoleMode. When ConsoleMode is true, any additional functions intended for use in the console (only) may be added.