Implement internationalization

[akx]

Based on @aapris ' comment below:

• Services.service_name
• Services.description
• Services.keywords
• Services.group

Also see https://github.com/6aika/api-palaute/blob/master/palaute.swagger.yaml#L50-L55

[aapris]

It seems only service list /services.json is i18n'ized in existing standard, so only it for now.

[aapris]

And the fields:

• service_name
• description
• keywords
• group