Add about page

pubspec.lock

@@ -645,6 +645,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.15.3"
+  http:
+    dependency: transitive
+    description:
+      name: http
+      sha256: "759d1a329847dd0f39226c688d3e06a6b8679668e350e2891a6474f8b4bb8525"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.0"
   http_multi_server:
     dependency: transitive
     description:
@@ -805,6 +813,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.0"
+  package_info_plus:
+    dependency: "direct main"
+    description:
+      name: package_info_plus
+      sha256: ceb027f6bc6a60674a233b4a90a7658af1aebdea833da0b5b53c1e9821a78c7b
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.0.2"
+  package_info_plus_platform_interface:
+    dependency: transitive
+    description:
+      name: package_info_plus_platform_interface
+      sha256: "9bc8ba46813a4cc42c66ab781470711781940780fd8beddd0c3da62506d3a6c6"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.1"
   path:
     dependency: "direct main"
     description:
@@ -1330,6 +1354,30 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.2.2"
+  url_launcher:
+    dependency: "direct main"
+    description:
+      name: url_launcher
+      sha256: "781bd58a1eb16069412365c98597726cd8810ae27435f04b3b4d3a470bacd61e"
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.1.12"
+  url_launcher_android:
+    dependency: transitive
+    description:
+      name: url_launcher_android
+      sha256: "78cb6dea3e93148615109e58e42c35d1ffbf5ef66c44add673d0ab75f12ff3af"
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.0.37"
+  url_launcher_ios:
+    dependency: transitive
+    description:
+      name: url_launcher_ios
+      sha256: "9af7ea73259886b92199f9e42c116072f05ff9bea2dcb339ab935dfc957392c2"
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.1.4"
   url_launcher_linux:
     dependency: transitive
     description:
@@ -1338,6 +1386,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.0.5"
+  url_launcher_macos:
+    dependency: transitive
+    description:
+      name: url_launcher_macos
+      sha256: "1c4fdc0bfea61a70792ce97157e5cc17260f61abbe4f39354513f39ec6fd73b1"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.6"
   url_launcher_platform_interface:
     dependency: transitive
     description: