Hide alias from public space creation (and automatically create)

### Your use case

#### What would you like to do?

When I am making a public space I want to do as little work as possible. Any work that I do, is work I want to be sure is valuable to making a good space - having a nice image, description, good quality rooms etc.

#### Why would you like to do it?

I don't like creative tasks feeling like admin, and I feel like creating a public space should feel like an easy, creative task. I just want my space to be good and I don't believe the alias is relevant to that. If it's myspecialspace:homeserver.com or myspecialspace1234:homeserver.com makes no real difference. If it really does matter to me one day I'd probably use a redirecting service or something to make a shorter/prettier URL.

#### How would you like to achieve it?

I'd like to not see an alias input and just have an alias assigned to my space in the background. This is how I think workspaces work in Slack, I create a workspace by naming it and when I invite people they get an email that has something like this.

### Have you considered any alternatives?

To not have an alias set at all but it does seem like they're very helpful for public spaces.

### Additional context

_No response_