Bsongis/x7d fixes (#4019)

* [X7D] Various fixes

[Others]
- Fixes the Mixer / Inputs MOVE / COPY problem on X9E
- Adds the copy/paste/rename feature in SDCARD menu on X7D/SKY9X
- Merges some duplicated code using the new directory structure
- Cosmetics

radio/src/strhelpers.cpp

@@ -237,7 +237,16 @@ char * getSwitchString(char * dest, swsrc_t idx)
     }
     else {
       *s++ = 'S';
+#if defined(PCBX7D)
+      if (swinfo.quot == 5)
+        *s++ = 'H';
+      else if (swinfo.quot == 4)
+        *s++ = 'F';
+      else
+        *s++ = 'A'+swinfo.quot;
+#else
       *s++ = 'A'+swinfo.quot;
+#endif
     }
     *s++ = "\300-\301"[swinfo.rem];
     *s = '\0';