Added dm-note

This script add dm-note which stores multiple one-line texts or codes so we can copy one of them when needed. I find this useful when dealing with multiple sentences or codes where I want them to be kept persistently in a file somewhere in HOME directory and copy them whenever I need one without them being deleted at later time unless I delete them myself.

Note: This script uses xclip and may need a little modification when wayland pr gets merged first