aoc2024: Implement day23 solution

I'm not proud of my implementation to last 2 days, but they work in a
reasonable time. I might optimize them later...

Problem is largely with my hash structures. Preallocating a lot of
elements before running day22 makes it run in less than half of the
current time.

userspace/aoc2024/day23/CMakeLists.txt

@@ -0,0 +1,9 @@
+set(SOURCES
+	main.cpp
+)
+
+add_executable(aoc2024_day23 ${SOURCES})
+banan_link_library(aoc2024_day23 ban)
+banan_link_library(aoc2024_day23 libc)
+
+install(TARGETS aoc2024_day23 OPTIONAL)