Fastfetch: refactor command line option parsing code

1. improve performance
2. remove `-c`
3. rename `--recache` to `--logo-recache`, and remove `-r`

src/fastfetch.h

@@ -45,7 +45,6 @@ typedef struct FFconfig
     FFstrbuf keyValueSeparator;
 
     bool showErrors;
-    bool recache;
     bool allowSlowOperations;
     bool disableLinewrap;
     bool hideCursor;