rust: Use AsRef<Path> and PathBuf in libraries

Use `AsRef<Path>` instead of `&Path`, &str, .... to be more versatile
and accept more input types. In addition, use `PathBuf` and `Path` for
paths instead of `String` and `str`.

Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>

rust/pv/src/error.rs

@@ -2,6 +2,8 @@
 //
 // Copyright IBM Corp. 2023, 2024
 
+use std::path::PathBuf;
+
 use crate::secret::UserDataType;
 
 /// Result type for this crate
@@ -26,7 +28,7 @@ pub enum Error {
 
     #[error("Cannot load {ty}  from {path}")]
     X509Load {
-        path: String,
+        path: PathBuf,
         ty: &'static str,
         source: openssl::error::ErrorStack,
     },