Optional support of Supply metadata

[XIII-th]

You can significantly improve user experience, if you support metadata structure of Supply plugin out of the box. As I see, GooglePlay and AppGallery use the same set of metadata and it won't be difficult to implement an adapter to read metadata.

Supply metadata                           AppGallery Connect metadata

└── fastlane                              └── fastlane
    └── metadata                              └── metadata
        └── android                               └── huawei
            ├── en-US                                 ├── en-US
            │   ├── changelogs                        │   ├── release_notes.txt
            │   │   ├── default.txt                   │   │
            │   │   ├── 100000.txt                    │   │
            │   │   └── 100100.txt                    │   │
            │   ├── title.txt                         │   ├── app_name.txt
            │   ├── full_description.txt              │   ├── app_description.txt
            │   └── short_description.txt             │   └── introduction.txt
            └── fr-FR                                 └── fr-FR
                ├── changelogs                            ├── release_notes.txt
                │   ├── default.txt                       │
                │   ├── 100000.txt                        │
                │   └── 100100.txt                        │
                ├── title.txt                             ├── app_name.txt
                ├── full_description.txt                  ├── app_description.txt
                └── short_description.txt                 └── introduction.txt

So, we can read app_name from title.txt, app_description from full_description.txt, introduction from short_description.txt file and release notes from <app_version>.txt file or the default.txt if <app_version>.txt is not found.