This way filenames in the blobstorage are just random hex numbers. This also allows us to get rid of
the `sanitize-filename` dependency.
This also requires `Param::Filename` to be set to "debug_logging*.xdc" for messages containing
logging webxdc-s, otherwise they are not detected properly. This is done in "fix:
Message::set_file_from_bytes(): Set Param::Filename", so don't forget to update senders as well.
It keeps timing out with the default timeout of 2 s on macOS runners.
Also fix comment in the integration test which
said that timeout is 1 minute but sets it to 3 minutes.
Set this timeout to 5 minutes as well.
Currently when a user sets up another device by logging in, a new key is created. If a message is
sent from either device outside, it cannot be decrypted by the other device.
The message is replaced with square bracket error like this:
```
<string name="systemmsg_cannot_decrypt">This message cannot be decrypted.\n\n• It might already help to simply reply to this message and ask the sender to send the message again.\n\n• If you just re-installed Delta Chat then it is best if you re-setup Delta Chat now and choose "Add as second device" or import a backup.</string>
```
(taken from Android repo `res/values/strings.xml`)
If the message is outgoing, it does not help to "simply reply to this message". Instead, we should
add a translatable device message of a special type so UI can link to the FAQ entry about second
device. But let's limit such notifications to 1 per day. And as for the undecryptable message
itself, let it go to Trash if it can't be assigned to a chat by its references.
