This commit adds a new subcommand to support symlinks within the same
mount. The command is intentionally still hidden since the support
isn't fully fleshed out, yet. Neither audit nor list know of links
and cross mount symlinks aren't supported either (and maybe never will).
RELEASE_NOTES=[ENHANCEMENT] Add gopass ln
Fixes#1820
Signed-off-by: Dominik Schulz <dominik.schulz@gauner.org>
