Kernel: Port VirtualConsole to LibVT :^)

Unfortunately this drops the feature of preserving VGA buffer contents.

Resolves https://github.com/SerenityOS/serenity/issues/2399

Kernel/CMakeLists.txt

@@ -139,10 +139,16 @@ set(ELF_SOURCES
     ../Libraries/LibELF/Validation.cpp
 )
 
+set(VT_SOURCES
+    ../Libraries/LibVT/Terminal.cpp
+    ../Libraries/LibVT/Line.cpp
+)
+
 set(SOURCES
     ${KERNEL_SOURCES}
     ${AK_SOURCES}
     ${ELF_SOURCES}
+    ${VT_SOURCES}
 )
 
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DKERNEL")