initial fastlane metadata from IzzyOnDroid

[IzzySoft]

this PR provides you with a "fastlane starter package" – to give it into your hands to define how your app is presented, and make it easy to keep descriptions & graphics in sync with your development. Some notes to sum them up in a place easy to find for you:

• the IzzyOnDroid Fastlane Documentation can guide you with maintaining the structures here
• take special care for limits, e.g. per-release changelogs can have max 500 chars, full_description.txt max 4,000 chars, graphics must have specific aspect ratios etc.
• you can have "bigger graphics" here; the IoD updater takes care to resize/optimize them as needed
• for the full_description.txt here I've used HTML compressed into a single line, to prevent the fdroid software converting each line break to a <br>. The tags used for this are supported by F-Droid.org as well, and to my knowledge even by PlayStore. Feel free to switch to what the above linked documentation describes as "Markdown Lite" if you prefer.
• whenever you add a new "type" of metadata that has not been there before (e.g. the first changelog, a featureGraphic if it wasn't yet present), please let us know so we can check and enable it.
• speaking of "new types": it would be great if you could add an icon. If you don't have any, maybe our IconMaker can help you 😉
• Details on all this in the linked documentation.
• Once merged, your changes will be synced whenever a new release is pulled in here – to make sure it stays up-to-date with the app itself.
• Should you have questions, be welcome to ask 😉

And now: Enjoy! 😃

Reference: #25

[neoblackxt]

Merged - thank you for putting this together, @IzzySoft! The structure is clear, and your notes on limits (500-char changelogs, graphic ratios) are noted for future additions. I'll look into adding an icon when I get to it, and will ping you whenever a new metadata type lands so you can enable it on your side.

[IzzySoft]

Thanks! When ready, don't forget to "seal" it via a new release (as that's where we usually pull it from). No rush, though. Just let me know once the icon is there, so I mark that to be included here as well.

[neoblackxt]

Icon is in, @IzzySoft - fastlane/metadata/android/en-US/images/icon.png (512x512), freshly designed: neon-cyan globe + 8-tooth gear on dark, matching the module's "WebView + developer options" theme. The app itself also got the same icon as a proper launcher icon (adaptive VectorDrawable on API 26+, PNGs below).

And it's sealed: v1.4.1 is out, so the metadata (icon included) should come along on your next pull. Please mark the icon type to be included, as you offered. Thanks again!