Add arguments close and quiet in gdal_run()

[ctoney]

@param close Logical value, FALSE by default. Set to TRUE to finalize
the algorithm immediately after it is run, which completes any pending
actions such as closing output datasets. This is useful if you do not need to
access the output as objects, e.g., when only generating file output for
later use. See GDALAlg$close().
@param quiet Logical value, FALSE by default. Set to TRUE to suppress
progress reporting along with various messages and warnings. Sets the value
of GDALAlg$quiet.

e.g.,

# finalize the algorithm immediately after it is run if only generating
# file output for later use:
gdal_run("raster convert", args, close = TRUE)

# or, assign to a variable and access algorithm output as a dataset object
alg <- gdal_run("raster convert", args)
ds <- alg$output()
alg$release()