testing/openocd-git: upgrade to 0_git20230228 and add udev and cmd_openocd subpkg

The first commit upgrades the package, the second adds two subpackages:

The udev rules subpackage function was added before, but the subpkg was never added to subpackages, so it was never actually build. This fixes the issue.

In addition the openocd-git-cmd-openocd subpackage is added that just adds a symlink from /usr/bin/openocd to openocd-git that is installed by default unless the openocd pkg is also installed. This will make life easier for users who only want to use the git version of OpenOCD without the release version installed as well.