"unrestricted" number of custom palettes (#4932)

- allow more than 10 custom palettes
- move palettes into CPP file
- Fix for minimizing cpal.htm (saves 2k of flash)
- shortened names in cpal, saves about 400 bytes of Flash after packing
- removed async from common.js loading to prevent errors on page loads if the file is not cached
- restricted nubmer of user palettes on ESP8266 to 10
- unrestricted number of user palettes on all other platforms (total max palettes: 256)
- added a warning when adding more than 10 palettes to let the user decide to risk it
- Bugfixes in palette enumeration, fixed AR palette adding
- AR palettes are now also added if there are more than 10 custom palettes

Co-authored-by: Blaž Kristan <blaz@kristan-sp.si>

wled00/util.cpp

@@ -230,7 +230,7 @@ uint8_t extractModeName(uint8_t mode, const char *src, char *dest, uint8_t maxLe
     } else return 0;
   }
 
-  if (src == JSON_palette_names && mode > (GRADIENT_PALETTE_COUNT + 13)) {
+  if (src == JSON_palette_names && mode > 255-customPalettes.size()) {
     snprintf_P(dest, maxLen, PSTR("~ Custom %d ~"), 255-mode);
     dest[maxLen-1] = '\0';
     return strlen(dest);