Add example of Finnish addresses

[jampukka]

An example on how-to-run hakunapi to serve addresses of buildings of Finland available from https://www.avoindata.fi/data/fi/dataset/rakennusten-osoitetiedot-koko-suomi

[teezip]

Read through sample readme, script and conf files under examples/finnish_addresses/.

Seems OK to me. Few minor comments below.

The section "Configuring and running hakunapi" in readme.md:

• after "Restart your tomcat ... http://localhost:8080/features" it would be nice to have a short list of actions needed after testing in localhost
• for example what parts in "addresses.properties" should be edited before deploying on a real test or prod server to get server resource links to match a real server
• no need to have instructions how to setup such server, that's out of scope, but about hakunapi configuration

Other comments:

• Maybe "api.contact.email" in "cfg/addresses.properties" should be left empty in demo?

[jampukka]

Added section about what to do next/preparing for production. Removed the fake email from example properties.

[teezip]

Thanks for changes. The readme with "preparing for production" section is good now.

[teezip]

As commented in #18 : The demo implementation behind https://beta-paikkatieto.maanmittauslaitos.fi/inspire-addresses/features/v1/ is now the demo of Hakunapi called "finnish-addresses" implemented by this pull request.

Some comments from developers (in Finnish) about instructions

Ohjeesta puuttui

1. komennosta HEADER:
   psql -d address_fin -c "\copy suomi_kunnat (sijaintikunta, nimi_suomi) FROM 'suomi_kunnat.csv' WITH (FORMAT CSV, DELIMITER ';' , HEADER)"

2. Tiedoston nimi oli väärin: (insert_simple_address.sql
   psql -d address_fin -f simple_addresses.sql

3. Tietoturva näkemys 

GRANT SELECT käyttjälle ja muut operaatiot tehtiin postgre käyttäjällä

[jampukka]

Fixed missing HEADER option from copy command, changed insert_simple_address.sql to the correct file name simple_addresses.sql, altered the scripts to suggest creating address_reader as read-only user and running the managerial parts of the scripts as postgres (or other superuser)