Update simple addresses demo service with a new open dataset

[teezip]

Demo service: https://github.com/nlsfi/hakunapi/tree/main/examples/finnish_addresses

Following quidelines are obsolete now, this dataset is not anymore available at avoindata.fi

• "The goal of this example project is to create an OGC API Features service with hakunapi to provide nationwide addresses of the buildings in Finland available freely from https://www.avoindata.fi/data/fi/dataset/rakennusten-osoitetiedot-koko-suomi"
• "Begin by downloading the .7z file containing all required data from https://www.avoindata.fi/data/fi/dataset/rakennusten-osoitetiedot-koko-suomi"

Docs and examples need updating and/or new sample dataset.

[jampukka]

Right, I'll have to update the example and generate similiar dataset