Add initial lang pack resources (#6035)

* Initial vs code lang packs

* Update resource to merge in ADS-specific strings

i18n/language-pack-de/vsc-extension-quickstart.md

@@ -0,0 +1,26 @@
+# Welcome to the German language pack
+
+## What's in the folder
+* `package.json` - the manifest file, defining the name and description of the localization extension. It also contains the `localizations` contribution point that defines the language id:
+```json
+        "contributes": {
+            "localization": [{
+                "languageId": "de",
+                "languageName": "German",
+                "localizedLanguageName": "Deutsch"
+            }]
+        }
+```
+* `translations` - the folder containing the translation strings
+
+
+To populate or update the `translations` folder as with the latest strings from transifex:
+- Check out the `master` branch of the [VS Code repository](https://github.com/Microsoft/vscode).
+   - Preferably, place the VSCode repo next to the language pack extension (so both have the same parent folder).
+   - `cd vscode` and run `yarn` to initialize the VS Code repo.
+- Get an API token from https://www.transifex.com/user/settings/api.
+- Set the API token to the environment variable `TRANSIFEX_API_TOKEN`.
+- `cd` to the VS Code repo
+   - If the language pack extension is placed next to the VS Code repository: `npm run update-localization-extension de`
+   - Otherwise: `npm run update-localization-extension {path_to_lang_pack_ext}`
+- This will download translation files to the folder `translations`, as well as populate a `translations` property in the `localizations` contribution point.