Just a cable stop. Lucky for you, they screw onto that Raleigh frame so no brazing necessary. You can likely source one from eBay, or some old-timer at your local bike shop might know where to get you one. Worst case scenario you get one that clamps around the tube like this: ORIGIN8 Alloy Cable Stop https://www.amazon.com/dp/B004FSVVN8/ref=cm_sw_r_cp_api_glt_fabc_YRKT00MHR0DTSF6PEJFV?_encoding=UTF8&psc=1
I bought cable cutters on Amazon for 12$ and they work great, see link below . No need for expensive park tool stuff for the occasional home mechanic. If you decide to cut you'd have to pull the cable out of the shifter a bit, take the housing out of the end caps, cut it with the wire cutters then reinstall. if you're doing it just because you switched your stem to a negative I'm not sure if it's lengthened by so much that is an obstruction. What if one day you decide to switch your stem back? this is what happened to me as I cut my cables in the front too short not realizing that one day I want to raise my stem up and now my housing is too short lol so I cannot run my bar tape all the way up. Good luck!
Cal Hawk Tools CPLWC8 7.5" Steel Wire Cutter https://www.amazon.com/dp/B009PD73QC/ref=cm_sw_r_apan_glt_fabc_N41AYD698EXK4VEPXD2C?_encoding=UTF8&psc=1
In addition to what /u/StgCan said, this tool has saved me a lot of trouble.
Get a trainer rear quick release skewer and go for it
Quwei Quick Release Rear Wheel Skewer Bike Wheel Skewers for Trainer Bicycle Cycling Back Rear Wheel Tire https://www.amazon.com/dp/B07C15XGMV/ref=cm_sw_r_cp_api_i_JJowFbRHRS1R8
The bars came with the bike - so standard Giant handlebars i guess?
The handlebar tape i purchased on Amazon. Find it here pink handlebar tape
Sure, it’s an Ibera, I got it from Amazon here. I’m really pleased with it as you can change the arms so that the bike is horizontal no matter what frame you have.