Add complete account dump to file

This commit introduces the ability to dump the complete content of an
account to a JSON file (compact or not depending on the provided format
option).

Example:

```sh
solana account -u m \
  --output json-compact \
  --output-file SRM_token.json \
  SRMuApVNdxXokk5GT7XD5cUUgXMBCoAz2LHeuAoKWRt
```

Note: Behavior remains untouched if format option `--output` is not
provided (only account data gets written to file).

(cherry picked from commit 0e9e67b65d)

cli/src/wallet.rs

@@ -462,9 +462,16 @@ pub fn process_show_account(
 
     let mut account_string = config.output_format.formatted_string(&cli_account);
 
-    if config.output_format == OutputFormat::Display
-        || config.output_format == OutputFormat::DisplayVerbose
-    {
+    match config.output_format {
+        OutputFormat::Json | OutputFormat::JsonCompact => {
+            if let Some(output_file) = output_file {
+                let mut f = File::create(output_file)?;
+                f.write_all(account_string.as_bytes())?;
+                writeln!(&mut account_string)?;
+                writeln!(&mut account_string, "Wrote account to {}", output_file)?;
+            }
+        }
+        OutputFormat::Display | OutputFormat::DisplayVerbose => {
             if let Some(output_file) = output_file {
                 let mut f = File::create(output_file)?;
                 f.write_all(&data)?;
@@ -475,6 +482,8 @@ pub fn process_show_account(
                 writeln!(&mut account_string, "{:?}", data.hex_dump())?;
             }
         }
+        OutputFormat::DisplayQuiet => (),
+    }
 
     Ok(account_string)
 }