Prompt Rendering Performance improvements

Pull Request :ghpull:`11933` introduced an optimisation in the prompt rendering logic that should decrease the resource usage of IPython when using the _default_ configuration but could potentially introduce a regression of functionalities if you are using a custom prompt.

We know assume if you haven't changed the default keybindings that the prompt will not change during the duration of your input – which is for example not true when using vi insert mode that switches between [ins] and [nor] for the current mode.

If you are experiencing any issue let us know.

Code autoformatting

The IPython terminal can now auto format your code just before entering a new line or executing a command. To do so use the --TerminalInteractiveShell.autoformatter option and set it to 'black'; if black is installed IPython will use black to format your code when possible.

IPython cannot always properly format your code; in particular it will auto formatting with black will only work if:

• Your code does not contains magics or special python syntax.
• There is no code after your cursor.

The Black API is also still in motion; so this may not work with all versions of black.

It should be possible to register custom reformatter, though the API is till in flux.

Arbitrary Mimetypes Handing in Terminal

When using IPython terminal it is now possible to register function to handle arbitrary mimetypes. While rendering non-text based representation was possible in many jupyter frontend; it was not possible in terminal IPython, as usually terminal are limited to displaying text. As many terminal these days provide escape sequences to display non-text; bringing this loved feature to IPython CLI made a lot of sens. This functionality will not only allow inline images; but allow opening of external program; for example mplayer to "display" sound files.

So far only the hooks necessary for this are in place, but no default mime renderers added; so inline images will only be available via extensions. We will progressively enable these features by default in the next few releases, and contribution is welcomed.

We welcome any feedback on the API. See :ref:`shell_mimerenderer` for more informations.

This is originally based on work form in :ghpull:`10610` from stephanh42 started over two years ago, and still a lot need to be done.