Added LiteAPKs as a source (#1799)

lib/app_sources/liteapks.dart

@@ -0,0 +1,87 @@
+import 'dart:convert';
+
+import 'package:http/http.dart';
+import 'package:obtainium/custom_errors.dart';
+import 'package:obtainium/providers/source_provider.dart';
+
+class LiteAPKs extends AppSource {
+  LiteAPKs() {
+    hosts = ['liteapks.com'];
+    name = 'LiteAPKs';
+  }
+
+  @override
+  String sourceSpecificStandardizeURL(String url, {bool forSelection = false}) {
+    RegExp standardUrlRegEx = RegExp(
+      '^https?://(www\\.)?${getSourceRegex(hosts)}/+[^/]+',
+      caseSensitive: false,
+    );
+    RegExpMatch? match = standardUrlRegEx.firstMatch(url);
+    if (match == null) {
+      throw InvalidURLError(name);
+    }
+    return match.group(0)!;
+  }
+
+  @override
+  Future<APKDetails> getLatestAPKDetails(
+    String standardUrl,
+    Map<String, dynamic> additionalSettings,
+  ) async {
+    var standardUri = Uri.parse(standardUrl);
+    var slug = standardUri.path
+        .split('.')
+        .reversed
+        .toList()
+        .sublist(1)
+        .reversed
+        .join('.');
+    Response res1 = await sourceRequest(
+      '${standardUri.origin}/wp-json/wp/v2/posts?slug=$slug',
+      additionalSettings,
+    );
+    if (res1.statusCode != 200) {
+      throw getObtainiumHttpError(res1);
+    }
+
+    var liteAppId = jsonDecode(res1.body)[0]['id'];
+    if (liteAppId == null) {
+      throw NoReleasesError();
+    }
+
+    Response res2 = await sourceRequest(
+      '${standardUri.origin}/wp-json/v2/posts/$liteAppId',
+      additionalSettings,
+    );
+    if (res2.statusCode != 200) {
+      throw getObtainiumHttpError(res2);
+    }
+    var json = jsonDecode(res2.body);
+
+    var appName = json['data']?['title'] as String?;
+    var author = json['data']?['publisher'] as String?;
+    var version = json['data']?['versions']?[0]?['version'] as String?;
+    if (version == null) {
+      throw NoVersionError();
+    }
+    var apkUrls =
+        ((json['data']?['versions']?[0]?['version_downloads'] as List<dynamic>?)
+                    ?.map((l) => l['version_download_link']) ??
+                [])
+            .map(
+              (l) => MapEntry<String, String>(
+                Uri.decodeComponent(Uri.parse(l).pathSegments.last),
+                l,
+              ),
+            )
+            .toList();
+    return APKDetails(
+      version,
+      apkUrls,
+      AppNames(
+        author ?? Uri.parse(standardUrl).host,
+        appName ?? standardUrl.split('/').last,
+      ),
+    );
+  }
+}