Add -n/--non-interactive option to juvix init

[paulcadman]

When moving to Package.juvix, the package configuration file cannot be empty. So it's convenient to have a quick way to create a Package.juvix file (previously you could run touch juvix.yaml.

This PR adds the -n / --non-interactive option to juvix init. This will create a default Package.juvix, using the name of the current directory to populate the package name.

Similarly for the interactive version of juvix init, if the name of the current directory is not a valid Juvix module then a fallback name is used instead.

For example:

$ mkdir /tmp/new-package
$ cd /tmp/new-package
$ juvix init -n
$ cat Package.juvix
module Package;

import PackageDescription.V1 open;

package : Package :=
  defaultPackage
    {name := "new-package";
     version := mkVersion 0 0 0;
     dependencies := [defaultStdlib]};

• Part of Remove support for the juvix.yaml package configuration file #2487