add german translation, update docs (#931)

- add german translation (following the changes in
https://github.com/maplibre/maputnik/pull/929)
- using an alphabecial order for the languages
- update the documentation with a step-by-step guide
- add myself as a helping person for german
- move the helping-users list to the implementation of new features
- update CHANGELOG.md
- add a link to the l18n README in the root README


![image](https://github.com/user-attachments/assets/2834f2c5-2cb7-4848-a6bf-24149be979ae)

src/locales/README.md

@@ -2,22 +2,57 @@
 
 The process of internationlization is pretty straight forward for Maputnik.
 
-In order to add a new translation you'll need to create a new folder and a json file with the relevant language code and make sure all the keys are translated.
-The following users can help you with the relevant languages:
+## Add a new language
 
-- English - @HarelM
-- Japanese - @keichan34
-- Simplified Chinese - @jieme
-- Hebrew - @HarelM
-- French - @lhapaipai 
+#### 1. Edit configuration
+
+In order to add a new translation you'll need to add it to the configuration files. Please put it in alphabetical order.
+
+- Open [/i18next-parser.config.ts](/i18next-parser.config.ts) and add the ISO Code of your language to the `locales` array.
+- Now, open [/src/i18n.ts](/src/i18n.ts) and add the ISO Code and localized name to the supported languages.
+
+#### 2. Add the localized strings
+
+Refresh the localization to generate a new directory under `/src/locales/` for your new language.
+
+```bash
+npm install
+npm run i18n:refresh
+```
+
+Replace every `__STRING_NOT_TRANSLATED__` value in the newly generated `translation.json` file with the according translation.
+Make sure all the keys are translated.
+
+#### 3. Test your new locale
+
+Finally, test your language locally by starting a local instance of Maputnik.
+
+```bash
+npm run start
+```
+
+Consider adding your name as a helping person for the translation of new features.
+
+## Add localization for a new feature
 
 If you happen to add a feature which needs some text to be translated, update the translation files.
 After running, check your working copy for files and add/correct as needed.
 
-```
+```bash
 npm run i18n:refresh
 ```
 
+The following users can help you with the relevant languages:
+
+| ISO Code | Language           | User                                       |
+|----------|--------------------|--------------------------------------------|
+| de       | German             | [@josxha](https://github.com/josxha)       | 
+| en       | English            | [@HarelM](https://github.com/HarelM)       | 
+| fr       | French             | [@lhapaipai](https://github.com/lhapaipai) | 
+| hr       | Hebrew             | [@HarelM](https://github.com/HarelM)       | 
+| ja       | Japanese           | [@keichan34](https://github.com/keichan34) | 
+| zh       | Simplified Chinese | [@jieme](https://github.com/jieme)         | 
+
 You can test the UI in different languages using the dropdown in the top menu
 Note that Maputnik automatically localize based on browser language settings and stores this language in local storage.
 You can use incognito mode to check a first time usage.