Refactor folder (#10475)

Move many third-party components' source codes from the src folder to a new folder called deps_src. The goal is to make the code structure clearer and easier to navigate.

deps_src/imgui/CMakeLists.txt

@@ -0,0 +1,28 @@
+cmake_minimum_required(VERSION 3.13)
+
+project(imgui)
+
+add_library(imgui STATIC
+    imconfig.h
+    imgui.cpp
+    imgui.h
+    imgui_demo.cpp
+    imgui_draw.cpp
+    imgui_internal.h
+    imgui_stdlib.cpp
+    imgui_stdlib.h
+    imgui_tables.cpp
+    imgui_widgets.cpp
+    # imgui STB
+    imstb_rectpack.h
+    imstb_textedit.h
+    imstb_truetype.h
+)
+
+target_include_directories(imgui PUBLIC
+    ${CMAKE_CURRENT_SOURCE_DIR}
+)
+
+if(Boost_FOUND)
+    target_link_libraries(imgui PRIVATE boost_headeronly)
+endif()