Move json parsing to cli

[dnomadb]

Right now json parsing of tile [{x}, {y}, {z}] coordinates is hidden inside the api:

supermercado/supermercado/uniontiles.py

Line 11 in fc6513c

tiles = sutils.tile_parser(inputtiles, parsenames)

We should move this to the CLI and add inputtiles as a sequence / iterable.