Undo PokeCodec's PRs

This commit undoes most of PokeCodec's PRs after the debate in chat. Some
harmless or completely superseded PRs have been left alone, as there is not
much benefit in attempting to undo them.

Reverts #1104, #1108, #1115, #1118, #1119, #1124, #1126, #1127, #1132, #1136,
#1137, #1139, #1140, #1144, #1148, #1149, #1150, #1153, #1155, #1177, #1179,
#1180, #1181, #1182 and #1183.

include/constants/rgb.h

@@ -1,10 +1,6 @@
 #ifndef GUARD_RGB_H
 #define GUARD_RGB_H
 
-#define GET_R(color) ((color) & 0x1F)
-#define GET_G(color) (((color) >> 5) & 0x1F)
-#define GET_B(color) (((color) >> 10) & 0x1F)
-
 #define RGB(r, g, b) ((r) | ((g) << 5) | ((b) << 10))
 #define RGB2(r, g, b) (((b) << 10) | ((g) << 5) | (r))
 #define _RGB(r, g, b) ((((b) & 0x1F) << 10) + (((g) & 0x1F) << 5) + ((r) & 0x1F))