[CLI] Allow selective copy between databases

[gorootde]

Summary

This feature will enable selective copy of entries between two distinct database files.

Examples

keepassxc-cli copy source.kdbx target.kdbx --tags to-be-copied
keepassxc-cli copy source.kdbx target.kdbx /groupPathToBeCopied

Context

I'd like to be able to automatically keep a separate database up to date with only a subset of the entries of source.kdbx

[droidmonkey]

Neat idea!