Don't handle missing timestamps as error

[janstarke]

There might be situations in which some OS doesn't have support for certain timestamps in a filesystem (e.g. https://doc.rust-lang.org/src/std/sys/unix/fs.rs.html#590) . This should not be an error which leads to program abort. Consider you wanted to analyze a prefetch file, then a missing creation date of the file wouldn't stop you from displaying all other information relating to this file.

fixes dfir-dd/dfir-toolkit#26

[SecSamDev]

I see it well, the only thing is that a logging system is already incorporated internally, there is no need to use "log". You can directly use the debug, warning, error macros provided by the framework itself.

[janstarke]

Please keep in mind that this change works fully correct since Rust 1.78 (see rust-lang/rust#121691). In previous versions of Rust, missing timestamps are not always handled as Unsupported, so your code will return an Error, instead of Ok(None). If this is of importance for your projects, you should add rust-version = "1.78" to your Cargo.toml

[SecSamDev]

Oh well, I don't think it's a good idea to limit the Rust version right now.
So I'll change the StdFS metadata to set None when an error is returned.
Thank you

[janstarke]

Think was another solution I was thinking about. You could filter for Error::Uncategorized with the message "creation time is not available for the filesystem", which is hard coded. This way, you won't lose other errors that might possibly occur