Removed the `autostow.sh` scipt. Its use was to call stow for every
folder in base directory and ignore certain folders. Both those
functions can be handled by stow on its own.
Stow allows defining per-directory ignore patterns with
`.stow-loca-ignore` files, which can be set to `.*` to completely ignore
a folder, just as before. And Stow can be called with a glob pattern to
automatically call it for every directory in the repository.
`.stowrc` additionally makes sure that all operations take place
targeting the home directory of the current user, since that is where
the dotfiles will (generally) be stored. Of course, this can be
overridden with the stow command-line options (see option precedence in
stow manual).
Finally, the bootstrap stow module adds an alias `dotlink` to the shell,
which allows fast (re-)stowing of all directories in the dotfile
repository. It uses a hard-coded location for the .dotfiles base
directory, so if the dotfiles are cloned anywhere else this has to be
customized.
Renamed bootstrap directory to _bootstrap to conform to default ignore
pattern of autostow.sh, and make it visually clear that this is a
special directory, not one used for the dotfiles itself.
