Add CSV support

[ppai-plivo]

Running fetch.js now also generates mcc-mnc-list.csv file.

$ ls -lh mcc-mnc-list.*
-rw-r--r--  1 user  staff   283K Apr  8 13:36 mcc-mnc-list.csv
-rw-r--r--  1 user  staff   763K Apr  8 13:23 mcc-mnc-list.json

Closes: #15

[ppai-plivo]

As documented here: https://csv.js.org/stringify/api/#sync-api

[ppai-plivo]

@pbakondy please let me know if this is ok.

[pbakondy]

@ppai-plivo please include only the code changes without the generated files in your patch

[ppai-plivo]

@ppai-plivo please include only the code changes without the generated files in your patch

Done 👍

I hope that next time you run fetch.js and update the list, mcc-mnc-list.csv is checked in and makes it to the repo. I need it to be downloadable from github, similar to mcc-mnc-list.json file.

[ppai-plivo]

@pbakondy Can you please take a look again ? Thanks.

[ppai-plivo]

Bump!