Add API documentation and underground station importer

- Introduced a new HTML documentation page for the oradio API, including a JavaScript file to handle dynamic content and API requests.
- Added a CSS file for styling the documentation page.
- Implemented an underground station importer script that fetches data from Radio-Browser and writes it to a JSON file.
- Created a stats module to compute and manage vote and play statistics for radio stations.
- Added a polyfill for modulepreload to ensure compatibility with older browsers.

data/seed/categories.json

@@ -1,17 +1,92 @@
 [
-  { "id": "starter",           "label": "Starter pack",        "icon": "★",  "order": 0 },
-  { "id": "dutch-public",      "label": "Nederlandse publieke","icon": "🇳🇱", "order": 1 },
-  { "id": "dutch-commercial",  "label": "Nederlandse commercieel","icon": "🇳🇱", "order": 2 },
-  { "id": "bbc",               "label": "BBC family",          "icon": "🇬🇧", "order": 3 },
-  { "id": "fip",               "label": "FIP family",          "icon": "🇫🇷", "order": 4 },
-  { "id": "underground",       "label": "Underground & curated","icon": "🌐", "order": 5 },
-  { "id": "ambient",           "label": "Ambient & lo-fi",     "icon": "🌫", "order": 6 },
-  { "id": "electronic",        "label": "Electronic",          "icon": "⚡", "order": 7 },
-  { "id": "jazz",              "label": "Jazz & blues",        "icon": "🎷", "order": 8 },
-  { "id": "classical",         "label": "Classical",           "icon": "🎻", "order": 9 },
-  { "id": "rock",              "label": "Rock & indie",        "icon": "🎸", "order": 10 },
-  { "id": "reggae",            "label": "Reggae & dub",        "icon": "🌴", "order": 11 },
-  { "id": "world",             "label": "World & regional",    "icon": "🌍", "order": 12 },
-  { "id": "soma",              "label": "SomaFM channels",     "icon": "📻", "order": 13 },
-  { "id": "nts",               "label": "NTS infinite mixtapes","icon": "♾", "order": 14 }
-]
+    {
+        "id": "starter",
+        "label": "Starter pack",
+        "icon": "★",
+        "order": 0
+    },
+    {
+        "id": "dutch-public",
+        "label": "Nederlandse publieke",
+        "icon": "🇳🇱",
+        "order": 1
+    },
+    {
+        "id": "dutch-commercial",
+        "label": "Nederlandse commercieel",
+        "icon": "🇳🇱",
+        "order": 2
+    },
+    {
+        "id": "bbc",
+        "label": "BBC family",
+        "icon": "🇬🇧",
+        "order": 3
+    },
+    {
+        "id": "fip",
+        "label": "FIP family",
+        "icon": "🇫🇷",
+        "order": 4
+    },
+    {
+        "id": "underground",
+        "label": "Underground & curated",
+        "icon": "🌐",
+        "order": 5
+    },
+    {
+        "id": "ambient",
+        "label": "Ambient & lo-fi",
+        "icon": "🌫",
+        "order": 6
+    },
+    {
+        "id": "electronic",
+        "label": "Electronic",
+        "icon": "⚡",
+        "order": 7
+    },
+    {
+        "id": "jazz",
+        "label": "Jazz & blues",
+        "icon": "🎷",
+        "order": 8
+    },
+    {
+        "id": "classical",
+        "label": "Classical",
+        "icon": "🎻",
+        "order": 9
+    },
+    {
+        "id": "rock",
+        "label": "Rock & indie",
+        "icon": "🎸",
+        "order": 10
+    },
+    {
+        "id": "reggae",
+        "label": "Reggae & dub",
+        "icon": "🌴",
+        "order": 11
+    },
+    {
+        "id": "world",
+        "label": "World & regional",
+        "icon": "🌍",
+        "order": 12
+    },
+    {
+        "id": "soma",
+        "label": "SomaFM channels",
+        "icon": "📻",
+        "order": 13
+    },
+    {
+        "id": "nts",
+        "label": "NTS infinite mixtapes",
+        "icon": "♾",
+        "order": 14
+    }
+]

data/seed/stations-allradio-nl.json

@@ -1449,4 +1449,4 @@
       }
     ]
   }
-]
+]