security/keepassxc276: Repocopy from security/keepassxc

Keepassxc > 2.7.6 removed support for Yubikey and other dongles.
Repocopy security/keepassxc to keepassxc276 in order to facilitate
updating keepassxc while allowing users to continue to use keepassxc 2.7.6
with Yubikey, using the opportunity to look for alternatives.

Suggested by: madpilot
PR: 279879
Approved by: lwhsu (MAINTAINER)