Cplus API: Add task to sync default layers to the InputLayers Data Model

[danangmassandy]

The default layers will be stored in specific directory in S3 bucket. The Cplus Django app should read this directory periodically to sync the latest default layers so we have the updated list in the plugin.

We might also try to read the metadata from the input layer, e.g:

{
    "name": "Final Alien Invasive Plant priority norm",
    "is_raster": 
    "description": "This is the description",
    "crs": 32735
    "resolution": [5, 15],
    "no_data": -9999
}

@zamuzakki does the metadata make sense? there might be another information to be added. cc: @amyburness

[zamuzakki]

@danangmassandy I'll update the metadata sample based on