primary key should be fullpath not id

[kugra-al]

eg: /obj/items/misc/alchemcy/glow_power.itm

This should always be unique. Then we can reuse id for the .itm id field. Speed won't be an issue with a few 1000 items.

• https://codersaurus.org/posts/laravel-model-string-primary-key-with-code-examples/
• https://stackoverflow.com/questions/34582535/laravel-5-2-use-a-string-as-a-custom-primary-key-for-eloquent-table-becomes-0 - old but pretty sure it's the same process
• https://dev.to/codeanddeploy/change-primary-key-and-timestamps-in-laravel-8-2ecb
• https://laravel.com/docs/9.x/migrations