Fixes bug introduced in zk-org#240 where interactive use of `zk new` results
in the command sitting indefinitely for user to supply user input.

This change introduces an explicit flag to `new` to indicate standard
input should be read for the content of the note.  The flag is called
`-i` on `--input`.

The flag name is somewhat confusing as there is a `--no-input` flag at
the global level.  I propose that we change that flag name to
`--no-prompt` as it more accurately describes the option.  To maintain
backwards compatibility, we define `--no-input` as an alias.

Apparently, kong `aliases` are only for commands. It did not work as I
had expected. At this point, `--no-input` has been removed. If we want
to keep it for backwards compatibility, I suppose we could add a new
hidden command line arg called `--no-input`. I defer to you for your
thoughts.

This reverts commit e2b9225.

This reverts commit c4ed7c0.

This option instructs the `new` command to read the initial contents of
the note from standard input.  This allows the use to pipe or use shell
redirection with note creation:

```sh
$ zk new --interactive < file.txt
$ echo "Initial content" | zk new --interactive
```