Merge branch 'day-7' into 'main'

src/day_7_1/command.rs

src/day_7_1/file_tree.rs

src/day_7_1/mod.rs

src/day_7_1/node.rs

src/day_7_2/command.rs

src/day_7_2/file_tree.rs

src/day_7_2/mod.rs

src/day_7_2/node.rs

src/main.rs