engine: zone: add small allocation optimization, reducing the size of <255 bytes allocations at the cost of less debug info

Keep it opt-in through a flag at pool alloc time.
Opt-in console related allocations, they are usually small enough strings.

engine/common/base_cmd.c

@@ -220,7 +220,7 @@ initialize base command hashmap system
 */
 void BaseCmd_Init( void )
 {
-	basecmd_pool = Mem_AllocPool( "BaseCmd" );
+	basecmd_pool = Mem_AllocPoolExt( "BaseCmd", MEM_SMALL_ALLOC_OPT );
 	memset( hashed_cmds, 0, sizeof( hashed_cmds ) );
 }