Localised notifications

[vitalidze]

For my private project I need localised notifications (in russian language). I can see two ways of implementation (which may probably be combined):

1. Add message template with following fields:

• title
• body

Template will be in Java Minimal Template Engine format.

I think the best way will be to have a message template per event type (or maybe even per device so notification will always be send for single device).

This will work for #139 too.

2. Add global language setting (like said in default language #141) and have localized messages in Messages.properties file. This global setting will also change the default language of entire traccar interface (so you won't have to edit traccar.html file anymore).

If someone has any thoughts on this - please express them :)

[antoniopaisfernandes]

Don't quite grasp every aspect of it but... I'll help translating whatever needs to.

From the translation maintenance point of view, the least number of files to address, the better (for now, we have 1 for desktop UI - per language - and 1 for mobile UI - all languages). But I reckon that coding structure shouldn't oblige by this...

[vitalidze]

Implemented, written news, updated article, latest and demo versions.