Even though it was originally designed to operate over dictionaries
only, this scatter sink actually can operate over arrays as well, and in
a more flexible manner than the TangoArrayScatterSink can.
TangoArrayScatterSink always scatters all its elements into separate
attributes, and it doesn't (seem to) support structured arrays. OTOH,
TangoObjectScatterSink supports filtering and path construction from the
input arrays, allowing us to define our own attributes in any way we
want, and supporting structured arrays as inputs too.

This commit removes the restriction in TangoObjectScatterSink's dtype so
that arrays can be fed into it, leaving the door open for array inputs.
Additionally, it also removes the check for the input data shape, both
because the input shape isn't used for any of the attributes'
configuration, and also because in principle there are actually no
restrictions in the shape of the input data.

Signed-off-by: Rodrigo Tobar <rtobar@icrar.org>