Ports: Register Browser in the Python webbrowser module

This makes the following work:

    >>> import webbrowser
    >>> webbrowser.open("http://serenityos.org")

As well as this well-known easter egg:

    >>> import antigravity

Pretty cool! :^)

Ports/python3/patches/ReadMe.md

@@ -23,3 +23,7 @@ Our stub implementation of `setlocale()` always returns `nullptr`, which the int
 ## `tweak-unsupported-printf-format-specifiers.patch`
 
 Replace uses of `%.Ns` with `%s` as the former is not supported by our `printf` implementation yet and would result in empty strings. It uses `snprintf` already, so this is safe.
+
+## `webbrowser.patch`
+
+Register the SerenityOS Browser in the [`webbrowser`](https://docs.python.org/3/library/webbrowser.html) module.

Ports/python3/patches/webbrowser.patch

@@ -0,0 +1,12 @@
+--- Python-3.9.5/Lib/webbrowser.py	2021-05-03 15:54:42.000000000 +0100
++++ Python-3.9.5/Lib/webbrowser.py	2021-05-06 14:21:34.242964786 +0100
+@@ -574,6 +574,9 @@
+             if shutil.which("w3m"):
+                 register("w3m", None, GenericBrowser("w3m"))
+
++    # SerenityOS Browser
++    register("Browser", None, BackgroundBrowser("Browser"))
++
+     # OK, now that we know what the default preference orders for each
+     # platform are, allow user to override them with the BROWSER variable.
+     if "BROWSER" in os.environ: