[Keyboard] Add Singa Kohaku (qmk#24309)

Co-authored-by: jack <jack@pngu.org>
Co-authored-by: Joel Challis <git@zvecr.com>
Co-authored-by: Duncan Sutherland <dunk2k_2000@hotmail.com>
Co-authored-by: Drashna Jaelre <drashna@live.com>

keyboards/zeix/singa/kohaku/config.h

@@ -0,0 +1,20 @@
+/*
+Copyright 2023 zeix (@itsme-zeix)
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#define RP2040_BOOTLOADER_DOUBLE_TAP_RESET
+#define RP2040_BOOTLOADER_DOUBLE_TAP_RESET_TIMEOUT 500U