Added VLC as a Source

lib/app_sources/vlc.dart

@@ -0,0 +1,62 @@
+import 'package:html/parser.dart';
+import 'package:http/http.dart';
+import 'package:obtainium/app_sources/html.dart';
+import 'package:obtainium/custom_errors.dart';
+import 'package:obtainium/providers/source_provider.dart';
+
+class VLC extends AppSource {
+  VLC() {
+    host = 'videolan.org';
+  }
+
+  @override
+  String standardizeURL(String url) {
+    return 'https://$host';
+  }
+
+  @override
+  Future<APKDetails> getLatestAPKDetails(
+    String standardUrl,
+    Map<String, dynamic> additionalSettings,
+  ) async {
+    Response res = await get(
+        Uri.parse('https://www.videolan.org/vlc/download-android.html'));
+    if (res.statusCode == 200) {
+      var dwUrlBase = 'get.videolan.org/vlc-android';
+      var dwLinks = parse(res.body)
+          .querySelectorAll('a')
+          .where((element) =>
+              element.attributes['href']?.contains(dwUrlBase) ?? false)
+          .toList();
+      String? version = dwLinks.isNotEmpty
+          ? dwLinks.first.attributes['href']
+              ?.split('/')
+              .where((s) => s.isNotEmpty)
+              .last
+          : null;
+      if (version == null) {
+        throw NoVersionError();
+      }
+      String? targetUrl = 'https://$dwUrlBase/$version/';
+      Response res2 = await get(Uri.parse(targetUrl));
+      String mirrorDwBase =
+          'https://plug-mirror.rcac.purdue.edu/vlc/vlc-android/$version/';
+      List<String> apkUrls = [];
+      if (res2.statusCode == 200) {
+        apkUrls = parse(res2.body)
+            .querySelectorAll('a')
+            .map((e) => e.attributes['href'])
+            .where((h) =>
+                h != null && h.isNotEmpty && h.toLowerCase().endsWith('.apk'))
+            .map((e) => mirrorDwBase + e!)
+            .toList();
+      } else {
+        throw getObtainiumHttpError(res2);
+      }
+
+      return APKDetails(version, apkUrls, AppNames('VideoLAN', 'VLC'));
+    } else {
+      throw getObtainiumHttpError(res);
+    }
+  }
+}