Update submodule URLs from yuzu-mirror to Citron repositories

Change the remote URLs for the following submodules to point to Citron's Git server:
- dynarmic
- discord-rpc
- sirit
- mbedtls
- breakpad
- oaknut

This migrates these dependencies from yuzu-mirror GitHub repositories to
Citron's self-hosted Git server while maintaining the same codebase.

.gitmodules

@@ -9,22 +9,22 @@
 	url = https://github.com/mozilla/cubeb.git
 [submodule "dynarmic"]
 	path = externals/dynarmic
-	url = https://github.com/yuzu-mirror/dynarmic.git
+	url = https://git.citron-emu.org/Citron/dynarmic.git
 [submodule "libusb"]
 	path = externals/libusb/libusb
 	url = https://github.com/libusb/libusb.git
 [submodule "discord-rpc"]
 	path = externals/discord-rpc
-	url = https://github.com/yuzu-mirror/discord-rpc.git
+	url = https://git.citron-emu.org/Citron/discord-rpc.git
 [submodule "Vulkan-Headers"]
 	path = externals/Vulkan-Headers
 	url = https://github.com/KhronosGroup/Vulkan-Headers.git
 [submodule "sirit"]
 	path = externals/sirit
-	url = https://github.com/yuzu-mirror/sirit.git
+	url = https://git.citron-emu.org/Citron/sirit.git
 [submodule "mbedtls"]
 	path = externals/mbedtls
-	url = https://github.com/yuzu-mirror/mbedtls.git
+	url = https://git.citron-emu.org/Citron/mbedtls.git
 [submodule "xbyak"]
 	path = externals/xbyak
 	url = https://github.com/herumi/xbyak.git
@@ -57,13 +57,13 @@
 	url = https://github.com/GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator.git
 [submodule "breakpad"]
 	path = externals/breakpad
-	url = https://github.com/yuzu-mirror/breakpad.git
+	url = https://git.citron-emu.org/Citron/breakpad.git
 [submodule "simpleini"]
 	path = externals/simpleini
 	url = https://github.com/brofield/simpleini.git
 [submodule "oaknut"]
 	path = externals/oaknut
-	url = https://github.com/yuzu-mirror/oaknut
+	url = https://git.citron-emu.org/Citron/oaknut.git
 [submodule "Vulkan-Utility-Libraries"]
 	path = externals/Vulkan-Utility-Libraries
 	url = https://github.com/KhronosGroup/Vulkan-Utility-Libraries.git