`save` doesn't allow array creation options

[d-v-b]

The save function defined in convenience.py doesn't allow specifying the array creation options like chunks, compressor, etc. The natural place for these parameters would be in **kwargs, but It looks like **kwargs in this function is used to contain a {name: numpy array} dict for the save_group function (which also fails to allow specifying chunks, compressor, etc).

Personally I'm not a fan of exposing partial functionality -- my feeling is that if we offer a routine for creating arrays, it should give users all the options available from the lower level array creation routine. I would be interested in reconsidering the design of the save function to make it a more complete expression of the array creation API.

cc @yuriyzubov

[jakirkham]

How about deprecating it? Seems we have several ways to do the same thing, which have evolved organically leading to an inconsistent user experience. Would be better to have one way to do things and support that well