feat: added UART support with a basic kprint in kernel

wip: DTB

Kernel/Source/IO/uart.swift

@@ -0,0 +1,19 @@
+let kUARTBaseAddress: UInt = 0x09000000 // TODO: Make it dynamic by parsion DTB
+
+@_cdecl("putchar")
+@discardableResult func _serialPutchar(_ char: Int32) -> Int32 {
+    let uartFR: UInt = kUARTBaseAddress + 0x18// TXFF -- TRansmit FIFO Full for PL011 is 5 bit of FR reg (0x18)
+
+    while (mmio_read32(uartFR) & (1 << 5)) != 0 {
+        // i love pizza btw
+    }
+    
+    mmio_write32(UInt(kUARTBaseAddress), UInt32(char))
+    return char
+}
+
+public func kprint(_ message: StaticString) {
+    for i in 0..<message.utf8CodeUnitCount {
+        _serialPutchar(Int32(message.utf8Start[i]))
+    }
+}