Feature: hyperlink support. (#665)

See the [OSC 8 page](https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda).
FTXUI support proposed by @aaleino in [#662](https://github.com/ArthurSonzogni/FTXUI/issues/662).

API:
```cpp
auto link = text("Click here") | hyperlink("https://github.com/FTXUI")
```

Fixed:https://github.com/ArthurSonzogni/FTXUI/issues/662

README.md

@@ -127,6 +127,7 @@ An element can be decorated using the functions:
   - `strikethrough`
   - `color`
   - `bgcolor`
+  - `hyperlink`
 
 [Example](https://arthursonzogni.github.io/FTXUI/examples_2dom_2style_gallery_8cpp-example.html)