Translations: use single JSON template for app translations instead of using translation tools

[webprofusion-chrisc]

Old translations were previously provided using webtranslateit but we no longer maintain this project as it doesn't integrate with our source control.

Website translations are redundant as browsers already provide this built in and instead we should only be maintaining a small core of translations for the app itself.

Based on: https://github.com/openchargemap/ocm-app/tree/master/src/assets/i18n

• Identify a subset of items to include in translations
• Create a script to remove unused items from existing translations,
• Rework translation item hierarchy to match the existing app instead of the website. Create mapping from old to new and apply that.
• Create a script to highlight translations missing from a given .json file and highlight extraneous items.