[Feature Request] Add support for opening files in exiftool-web via PWA Web App Manifest

[BarnMTB]

Hello and thank you for your effort in creating exiftool-web. It's pretty much the only modern Exif tool that I can find.

It'd be great to be able to share files to exiftool-web for easier access.
Right now, to inspect a file with exiftool-web, the exiftool-web website have to be opened first before the file can be selected.

PWA (via Web App Manifest) now offers the ability for installed webapps to register itself as a share target on System Share menus.
https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps/Manifest/Reference/share_target
https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps/How_to/Share_data_between_apps#handling_shared_data_from_other_apps

Left: System Share menu on Windows 11 | Right: Entrypoints to System Share menu in Windows 11's File Explorer

This meant that exiftool-web can appear among the list of apps that user can share to in the System Share menu.

After the user installed exiftool-web as a PWA via their browser, exiftool-web will appear among the list of apps in the System Share menu. And now the user can simply select files they want to inspect, and select Share either in the File Explorer's toolbar or in the right-click context menu, eliminating the need to first navigate to exiftool-web first before being able to open the file.

Design consideration

Some newer OS allow the user to remove location data or edit the image via the System Share menu; a good privacy feature in normal use-cases.
When the user shared an image to exiftool-web, a small note can be shown to remind the user to make sure that location data stripping should be turned off when sharing to exiftool-web, and they should avoid using options in there that modify the files.
This could also allow for an interesting use-case where people can see what data are left when they use these new privacy-preserving features.

Other option

In addition to being a share target in the System Share menu, PWA also allow installed webapps to register directly as a file handler, allowing exiftool-web to sit in the "Open with..." options alongside other other apps installed on the system that can open the file (such as image viewers and editors)
https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps/Manifest/Reference/file_handlers
https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps/How_to/Associate_files_with_your_PWA