Merge with a different database using the current password

[sukhmel]

Is your feature request related to a problem? Please describe.
Merging to sync conflicts is sometimes painful. I usually rename the database and merge, but I accidentally clicked "Save" instead of "Merge" last time, losing an update.

Describe the solution you'd like
Be able to do "Merge" operation to a database with a different path.

Describe alternatives you've considered
Make a backup of the current database before (overwriting) saving to be able to undo overwrite.

Additional context
Desktop KeePassX allows to merge a different database but that requires inputting a password. I assume, most of the time merging means the user wants to merge updates from the same database, so it would be great to be able to use the currently open database's key to try to merge a separate file into the database.