Add new groups confirmation page

[thomasiles]

Add a new page with content to slow when creating a new group

Trello card: https://trello.com/c/KETW4If8/3099-add-a-new-page-after-a-user-clicks-create-a-group

This PR adds a new page between clicking "Create group" and giving the group a name. It also updates the content on the new groups page.

The new page is to confirm the user wants to create a group and give them more information about what a group is. The content is different for organisations which have an admin.

The existing new group page can still be accessed directly through URL. The create group button link has been changed to this new page.

Note

I made up some content for the validation message the user sees when they don't check yes or no and submit the page.

Without org admins

With org admins

Without selecting yes/no

The updated new group page

Things to consider when reviewing

• Ensure that you consider the wider context.
• Does it work when run on your machine?
• Is it clear what the code is doing?
• Do the commit messages explain why the changes were made?
• Are there all the unit tests needed?
• Do the end to end tests need updating before these changes will pass?
• Has all relevant documentation been updated?

[github-actions]

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