Allow undef for logout_uri and logout_redirect

[abujeda]

logout_uri and logout_redirect default values are managed in ood-portal application.
Without the Optional[String] settings for these properties, it is not possible to remove the logout redirect from Apache.

There are cases, when multiple domains and OIDC are used, that a more complex logout redirect is required.
This can be now accomplished using the new custom_vhost_directives like so:

openondemand::custom_vhost_directives:
  - 'RewriteRule ^/logout$ /oidc?logout=https://%{literal("%")}{HTTP_HOST} [R=301,L]'

This is simply propagating the current domain to the OIDC identity provider for any domain used within OOD.

Although the Redirect directive created with the default values for logout_uri and logout_redirect do not affect the functionality of the RewriteRule as the custom_vhost_directives are printed first, it will create a cleaner config.

[abujeda]

relates to #3442

[treydock]

You only need to change the datatype. You don't need to remove the defaults. Linters won't let Optional be used without default being undef I believe:

Variant[String[1], Undef]

Could try this too but I think linters will complain.

Optional[String[1]]

In Hiera you could set:

openondemand::logout_uri: ~

So you can force undef without removing the default from this module.

The reason I don't want to remove the defaults is I try to keep this module to have same defaults as OnDemand which helps with maintenance.

[treydock]

Suggested change

	Optional[String] $logout_uri = undef,
	Optional[String] $logout_redirect = undef,
	Variant[String[1], Undef] $logout_uri = '/logout',
	Variant[String[1], Undef] $logout_redirect = '/pun/sys/dashboard/logout',

[abujeda]

Thanks - I have updated with the changes to the REFERENCE.md too

[treydock]

This is released as 5.0.1.