[Cin] add Frame on PiP on manual

I have added a new section to the Real-World appendix of the manual. It consists of adding a frame to a Picture in Picture and is based on a post in our forum. I enclose the latex file with image and also the text in odt for those who would like to review it. See if it is OK for you. Link to the files: https://ufile.io/zfshf1ct