Add automatic direction recognition

[Davoodeh]

Brief outline of the feature request

Add one or more environment that each use a their own respective method of
automatically detecting text direction.

This will greatly improve the UX and noob-friendlyness of LaTeX as a whole
alongside the code readability.

• This was already discussed in the Telegram and @kvafa thought it's possible
  in an unknown future time.

Check/indicate

• Relevant to the xepersian package
• The bidi package issue tracker has been searched for similar issues?
• The xepersian package issue tracker has been searched for similar issues?

Minimal example

\usepackage{bidi}
\begin{document}

\begin{autodir}{unicode,base=ltr}
This is a bidi text that has a phrase in it like سلام دنیا.
Which would likely be rendered as دنیا سلام if not for this environment.

With this `autodir` environment, the bidi direction will
automatically add the `rl` macro to it before processing.
\end{autodir}
  
\end{document}