Removal of the inn shortcut symlink/binary from OS packages

[mcginty]

We're going to be phasing out inn being packaged in favor of using normal shell aliases.
Unfortunately, it's neither recommended nor often possible to auto-alias for your shells, so this change will require you to be the one to create the alias.

fish

abbr -a inn innernet

zsh

echo 'alias inn="innernet"' >> ~/.zshrc

bash

echo 'alias inn="innernet"' >> ~/.bashrc

This will allow manpages and completions to work as expected, and is in general less of a hack than sometimes needing to include two copies of the same binary depending on the features of an OS's package manager.

Starting with version 1.5.2, there will be a warning printed when inn is called, and in the next version release the inn binary will be replaced by a stub that returns an error. After some time, the stub will be removed all together.

See #175 for the original conversation and justifications.

[alerque]

I think this can be closed and probably un-pinned as well given the timeline and current state of things.

[strohel]

Oh yes, thanks for helping us keeping the issues clean, @alerque.