Soul Anchor Block

Adds a soul anchor block that lets you set your respawn point in the Nether.

Craft it with a nether star surrounded by 8 obsidian, and it drops the obsidian back when broken.
Right click with glowstone to charge it up to 4 times, and right click again to set your respawn, and each death uses up one charge, and it glows brighter the more charges it holds.

Use a charged one outside the Nether and it explodes, which is intentional game design, and the dimension whitelist, charge item, max charges, explosions, and whether beds still set spawn can all be changed in config.