Function normalize_path

pub fn normalize_path(path: &str) -> String

Make sure all operation are constructed by normalized path:

• Path endswith / means it’s a dir path.
• Otherwise, it’s a file path.

Normalize Rules

• All whitespace will be trimmed: abc/def => abc/def
• Repeated leading / will be trimmed: ///abc => /abc
• Internal // will be replaced by /: abc///def => abc/def
• Empty path will be /: `` => /