Add URI-related operators to IOUtils

[lemmy]

https://github.com/tlaplus/tlaplus/commit/1eb815620dedc696a5a637944853129595c47216#diff-364040e3b4487febdb3378d1e3a325421763d819b32c40520360494933a8e263R12 does not work for absolute paths. We should consider adding URI-related operators such as Dirname, Basename, Extname, ...