scuba2: update config/recipe parameters for GBS

GBS has a new set of makemap config parameters that now try to deal
with the "blobs" that sometimes appear when doing extended reductions.

GBS also has a requirement that the mapmaker does NOT chunk the data,
so set the NOCHUNKING parameter for the pipeline to trap.
SCUBA2: add NOCHUNKING

This parameter determines whether or not the pipeline aborts after
checking if the data need to be split into chunks for
processing. Default value is 0 (do not check). Currently if any
non-zero value, the pipeline will abort only if the data need to be
chunked (i.e. memcheck = 2 is not yet supported).
SCUBA2: add support for checking for data chunking

The recipe parameter NOCHUNKING should be set to any non-zero value in
order to force the mapmaker to exit if it determines that the data
need to be chunked. Currently only memcheck=1 is supported (see
makemap documentation for further details) but that can change if
users request it.