Add links to tile provider authentication docs (#914)

This probably confused some people in the past, since vector tiles won't
even display an access denied image ;)

Before (no information on access keys and where to get them):

<img width="411" alt="image"
src="https://github.com/user-attachments/assets/8820fb20-bda4-460c-9cc9-8fec5daa480d">

After (add links to providers in info callout + add a field for Stadia
Maps API keys):

<img width="395" alt="image"
src="https://github.com/user-attachments/assets/91ee732c-b3f5-45f8-81a6-8d896a93f644">

---------

Co-authored-by: Harel M <harel.mazor@gmail.com>
Co-authored-by: Joscha <34318751+josxha@users.noreply.github.com>
Co-authored-by: Hugues Tavernier <hugues.tavernier@protonmail.com>
Co-authored-by: Keitaroh Kobayashi <keita@kbys.me>

src/locales/zh/translation.json

@@ -34,7 +34,6 @@
   "Style Settings": "样式设置",
   "View": "视图",
   "Color accessibility": "颜色可访问性",
-  "Language": "语言",
   "Help": "帮助",
   "Comments for the current layer. This is non-standard and not in the spec.": "当前图层的注释。注意：这不是标准功能，可能与其他库不兼容。",
   "Comments": "注释",
@@ -73,8 +72,8 @@
   "Collapse": "折叠",
   "Expand": "展开",
   "Add Layer": "添加图层",
-  "Zoom:": "缩放:",
   "Search": "搜索",
+  "Zoom:": "缩放:",
   "Close popup": "关闭弹出窗口",
   "cursor:": "光标:",
   "center:": "中心:",
@@ -82,7 +81,6 @@
   "Close modal": "关闭模态框",
   "Debug": "调试",
   "Options": "选项",
-  "<0>Open in OSM</0> — Opens the current view on openstreetmap.org": "在 openstreetmap.org 打开当前视图",
   "Export Style": "导出样式",
   "Download Style": "下载样式",
   "Download a JSON style to your computer.": "将JSON样式下载到您的电脑。",
@@ -177,10 +175,15 @@
   "Error:": "错误：",
   "MapTiler Access Token": "MapTiler 访问令牌",
   "Public access token for MapTiler Cloud.": "MapTiler Cloud 的公共访问令牌。",
+  "Learn More": "__STRING_NOT_TRANSLATED__",
   "Thunderforest Access Token": "Thunderforest 访问令牌",
   "Public access token for Thunderforest services.": "Thunderforest 服务的公共访问令牌。",
+  "Stadia Maps API Key": "Stadia Maps API 密钥",
+  "API key for Stadia Maps.": "Stadia Maps 的 API 密钥",
   "Style Renderer": "样式渲染器",
   "Choose the default Maputnik renderer for this style.": "为这种样式选择默认的Maputnik渲染器。",
+  "Language": "语言",
+  "<0>Open in OSM</0> — Opens the current view on openstreetmap.org": "在 openstreetmap.org 打开当前视图",
   "Layer options": "图层选项",
   "Paint properties": "绘制属性",
   "Layout properties": "布局属性",