Refactor file io tests to support different file io storage

[Xuanwo]

          > * Could we add some tests to verify it? I think it should be easy since we have it as default feature.

Current test is not extsiable for different storage service, please allow me to complement them in a new PR. For example, I can refactor test_local_input_file, test_delete_local_file, ... to make them work on different file io instead.

Could we have a simple doc to explain how to use it? At least for me, it's not straight forward without refering to opendal's doc.

Sure, I will add this.

Originally posted by @Xuanwo in #481 (comment)