fix title and version and contact URLs

[dietervu]

Title should be Digital Object Gateway

I get a 404 for both:

• https://alpha-dog.clarin.eu/about
• https://alpha-dog.clarin.eu/contacting

[dietervu]

Would make sense to also have a Registered Repositories menu item. The Swagger links should be renamed OpenAPI and could have a place under a Help menu item - see switchboard.clarin.eu for an example

[MichalGawor]

URL's fixed. /contacting never existed, contact information is under /contact

I am not sure about moving the table of registered repositories to another section. In addition to propagation of the underlying error (shall no longer show 500) user should have easy access to the status table to see that issue lies on the side of the repository they try to reach. If it gets moved to separate tab I doubt many people will look for it.