Merge dom and component focus

[horrifyingHorse]

Following the approach discussed in #970 to resolve #935

[horrifyingHorse]

Greetings,

I suppose it's fixed now, although i would like to add that i had to accommodate the SetCursor of Focus::Render in Node::Render, anywhere else, it kept messing up the cursor on input.

Is there any better way to do it?

[ArthurSonzogni]

Excellent!
At first sight, it looks exactly as I hoped!

I am quite busy at the moment. I will take a deeper look as soon as possible. Thank you very much for making this patch!

[horrifyingHorse]

There is an issue with the cursor. In Input component, the cursor is not positioned correctly inside the input box.

I've cross checked it with the previous commits and it seems the issue arises in 511a294

---

to recreate

#include <ftxui/component/component_options.hpp>
#include "ftxui/component/component.hpp"
#include "ftxui/component/screen_interactive.hpp"

using namespace ftxui;

int main() {
  auto screen = ScreenInteractive::Fullscreen();
  std::string inp;
  auto input = Input(&inp, "input", InputOption::Spacious());
  auto display = Renderer(input, [&] {
    return vbox({
      hbox({
        filler(),
        vbox({
          text("Banner") | center,
        }) | size(WIDTH, EQUAL, 40) | border,
        filler()
      }),
      filler(),
      input->Render()
        | size(WIDTH, EQUAL, 20) | size(HEIGHT, EQUAL, 7) | center
    });
  });

  screen.Loop(display);
}