Command: major code refactoring

ditto; and multi-command support was removed in favor of JSON config
support

src/modules/command/option.h

@@ -0,0 +1,14 @@
+#pragma once
+
+// This file will be included in "fastfetch.h", do NOT put unnecessary things here
+
+#include "common/option.h"
+
+typedef struct FFCommandOptions
+{
+    const char* moduleName;
+    FFModuleArgs moduleArgs;
+
+    FFstrbuf shell;
+    FFstrbuf text;
+} FFCommandOptions;