Internationalise the plugin

[jmshal]

The plugin obviously needs the support for languages first, but after it has, the following languages would be cool to have.

• German
• French
• Korean (reserved, translator scheduled) Translation: Korean #23
• Polish Translation Polish #27

No Google translate! PRs are welcome.

[jmshal]

It should be known that every release will defer until required translations are done for ALL languages supported. For that reason, it will be up to the PR/issue to sort out any translations for any specific feature.