refactor(sql): do not expose rusqlite Error type in query_map methods

We use query_and_then() instead of query_map() function now.
The difference is that row processing function
returns anyhow::Result, so simple fallible processing
like JSON parsing can be done inside of it
when calling query_map_vec() and query_map_collect()
without having to resort to query_map()
and iterating over all rows again afterwards.

src/sync.rs

@@ -202,7 +202,11 @@ impl Context {
             .query_map(
                 "SELECT id, item FROM multi_device_sync ORDER BY id;",
                 (),
-                |row| Ok((row.get::<_, u32>(0)?, row.get::<_, String>(1)?)),
+                |row| {
+                    let id: u32 = row.get(0)?;
+                    let item: String = row.get(1)?;
+                    Ok((id, item))
+                },
                 |rows| {
                     let mut ids = vec![];
                     let mut serialized = String::default();