build: Refactor CMake build system

This new architecture decomposes the project into several distict static
libraries: common, host, kvm, and frontend.

By using static libraries, changes within one module will only require
that library to be re-linked, rather than recompiling and re-linking the
entire executable.

The third party library ImGui is now built as a static library target.

Signed-off-by: Ronald Caesar <github43132@proton.me>

src/common/IoFile.cpp

@@ -4,7 +4,6 @@
 
 #include "IoFile.h"
 
-#include "Assert.h"
 #include "Error.h"
 #include "Logging/Log.h"
 #include "PathUtil.h"
@@ -287,7 +286,6 @@ uptr IOFile::GetFileMapping()
     mapping = hfile;
 
     fileMapping = std::bit_cast<uptr>(mapping);
-    ASSERT_MSG(fileMapping, "{}", Base::GetLastErrorMsg());
     return fileMapping;
 #else
     fileMapping = fileno(file);