The Pulumi CLI currently has two "display modes" -- one for rendering
diffs and one for rendering program updates. Neither of these is
particularly well-suited to `pulumi query`, which essentially needs to
render stdout from the query program verbatim.
This commit will add a separate display mode for this purpose:
* In interactive mode, `pulumi query` will use the display spinner to
say "running query". In non-interactive mode, this will be omitted.
* Query mode will print stdout from the query program verbatim, but
ignore `diag.Infoerr` so that they're not double-printed when they're
emitted again as error events.
* Query mode also does not double-print newlines at the end of diag
events.
