I18n updates

Add version tag for now

**New features**

/

**Fixes**
* Fix preset button order update (#11)
* Fix style file path - icons can now be found

**Refactoring**
* Reorder source code - move to org.openstreetmap.josm.plugins.indoorhelper
* Formatting + Clean code changes

**General**
* i18n update
* Add contribution guide
* Add install guide
* Update README

Fix spelling

Fix IFCSITE element check

Fix gradle dependency