`--clip` option

[russbiggs]

As a higher level feature atop the --bbox option an option to pass a GeoJSON polygon or multi-polygon could save users a number of steps to define a bounding box. The proposed flow would be as follows:

• --clip takes a path to a geojson file on the user's system e.g. --clip ./abq_bounds.geojson
• openaq-cli will open the file and parse the GeoJSON (validating that it is in fact a polygon or multipolygon)
• the tool would calculate a bounding box
• pass the bounding box to the API via the client

Additionally, after receiving the results the CLI could clip the result set to the input polygon. An optional --no-clip could also be included to bypass the final clipping, making geojson a shortcut to generating a bounding box only.

[russbiggs]

I'm now leaning more to the option name --clip after reviewing a couple other CLIs with similar functionality this seems a bit more standard. It will also have the advantage of eventually allowing multiple file types, not just GeoJSON.

Instead of the --no-clip option i think we should instead overload the --bbox to allow GeoJSON polygon input.