Use internal domains for Image CDN

[rpsu]

Use images[-test].cdn.yle.fi domain with image binary requests (Cloudinary requests) for future compatibility reasons as per the (recently) updated documentation.

EPIC issue:

• Yleisradio/images-api-v2#64

Code references:
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L27
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L63
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L108
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L153
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L198
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L243
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L288
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L333
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L378
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L423
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L468
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L513
https://github.com/https://github.com/Yleisradio/avoin-voitto/blob/2ba4b5132dafc270e495f65c433ad260d8eb0dac/data/mestis/league.json#L558

[rpsu]

https://github.com/search?q=repo%3AYleisradio%2Favoin-voitto%20cloudinary.com&type=code still produces quite a few interal domain usages. @JarkkoYle