refactor(store)!: change Store's method and error names

The changes in this commit were motivated due to a bug in the
`StoreFile` which caused old data to be lost if the file was `open`
instead of created and new data was appended. The bugfix later motivated
a general name cleanup in StoreFile's methods and errors and some minor
changes in their signatures. IterError was replaced by StoreError, which
now includes the `IterError` variants, making it replaceable. The new
StoreFile methods are:
- create: create file in write only mode or fail if file exists.
- load: open existing file, check integrity of content and retrieve
  Store.
- append: add new changesets to Store. Do nothing if changeset is empty.
- dump: aggregate and retrieve all stored changesets in store.
- load_or_create: load if file exists, create if not, and retrieve
  Store.

refactor: update all call names to bdk_file_store::Store methods

Author: nymius

crates/file_store/src/entry_iter.rs

@@ -1,3 +1,4 @@
+use crate::StoreError;
 use bincode::Options;
 use std::{
     fs::File,
@@ -37,7 +38,7 @@ impl<T> Iterator for EntryIter<'_, T>
 where
     T: serde::de::DeserializeOwned,
 {
-    type Item = Result<T, IterError>;
+    type Item = Result<T, StoreError>;
 
     fn next(&mut self) -> Option<Self::Item> {
         if self.finished {
@@ -63,7 +64,7 @@ where
                         }
                     }
                     self.db_file.seek(io::SeekFrom::Start(pos_before_read))?;
-                    Err(IterError::Bincode(*e))
+                    Err(StoreError::Bincode(*e))
                 }
             }
         })()
@@ -80,29 +81,3 @@ impl<T> Drop for EntryIter<'_, T> {
         }
     }
 }
-
-/// Error type for [`EntryIter`].
-#[derive(Debug)]
-pub enum IterError {
-    /// Failure to read from the file.
-    Io(io::Error),
-    /// Failure to decode data from the file.
-    Bincode(bincode::ErrorKind),
-}
-
-impl core::fmt::Display for IterError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            IterError::Io(e) => write!(f, "io error trying to read entry {}", e),
-            IterError::Bincode(e) => write!(f, "bincode error while reading entry {}", e),
-        }
-    }
-}
-
-impl From<io::Error> for IterError {
-    fn from(value: io::Error) -> Self {
-        IterError::Io(value)
-    }
-}
-
-impl std::error::Error for IterError {}