Examine Multi-Language support

[DavidBaldsiefen]

IMIS needs multilanguage support for two reasons:

1. Users in Germany are potentially not fluent in the german language
2. In the future, IMIS should be fit to be used internationally

Currently, every label/text/... is hardcoded. While this feature isn't top priority, we can save us a lot of work in the future by tackling this issue now.

The first step would be to find out different ways to implement multi-language support, and then decide which one we'll use.

See also #221

[jabrandes]

VueI18n looks suitable for that purpose. It integrates into Vue with a vue-cli plugin and eslint rules available. It is also the system that issue #221 refers to.