Implement the proc filesystem #25

Maybe turn the ramfs into a trait instead which would make it easier to make in memory file systems with custom file contents type without needing to bloat the ramfs impl itself.

• Add /proc/cpuinfo to the proc filesystem (so uwufetch can show the cpuinfo)
• Make uwufetch read and parse the cpuinfo provided in /proc/cpuinfo using serde-json and print it in the screen fetch.