[CHORE] Change translation JSON format (Easy but lot of changes)

[Zagrios]

Problem

At the beginning of the project, we chose this format for translations:

"search-bar": {
    "search-placeholder": "Search a map",
    "filters-btn": "Filters",
    "dropdown": {
        "export-maps": "Export maps",
        "delete-maps": "Delete maps",
        "delete-duplicate-maps": "Delete duplicates"
    }
},

So a translation key would be search-bar.dropdown.export-maps

This was a bad choice.
This format introduces a lot of duplication, makes it time-consuming to find the right place to add new translations, and complicates inferring the correct translation key to use in React components. Additionally, it increases the risk of using invalid translation keys.

Solution

We need to switch to this format for translations:

"Search a map": "Search a map",
"Filters": "Filters",
"Export maps": "Export maps"
"Delete maps": "Delete maps"
"Delete duplicates": "Delete duplicates"

(For the English translation, keys and values will almost always be the same)

With this format, there's no need to figure out where to place new translations : just add them at the end.
All duplicated translations will be merged into a single translation key.
We can infer a Translatable type directly from the translation file:

And any invalid translation key will be handled by TypeScript:

[AltyFox]

Certainly doesn't look nearly as pretty, but certainly does make it easier