Add support for KeeLink - send passwords to devices without KeePass through QR code

**Problem**
Sometimes one needs to login somewhere on an external device - e.g. a friends computer, meeting room at work... These devices usually do not have (any) KeePass installed (and furthermore storing the database on such device would be a security risk), which makes logging in difficult. Usual solutions include writing the password manually, or having an USB stick with a portable KeePass installation together with the database.

**Describe the solution you'd like**
KeePass2Android has a [plugin called KeeLink](https://play.google.com/store/apps/details?id=it.andreacioni.kp2a.plugin.keelink&pli=1) , which enables user to share a password by scanning a QR code on this website https://keelink.fly.dev/ . The password is then sent encrypted to the said website and copied into users clipboard on the target device.

I could not find source code for the KP2A plugin, but the [KeeLink repository](https://github.com/andreacioni/KeeLink) has all the source code for the KeeLink server (supports self hosting), this should make it possible (and maybe not that difficult?) for KeePassDX to integrate with KeeLink.

**Describe alternatives you've considered**
Another plugin for KP2A exists https://www.inputstick.com/ , which solves the same problem, although with a hardware solution.

Tagging @andreacioni

Start by reading the KeeLink repository and the linked KeeLink website, then compare their flow with the KeeLink plugin described for KeePass2Android. Done should mean KeePassDX can share a selected password through an encrypted QR-code flow to a device without KeePass installed.

Written by the indexing model from the issue text.