Add configuration info into "Set up Azure"

What does this MR do?

To set up Azure as a SAML SSO identity provider, as a first step, users must first find either of the following:

• The Assertion consumer service URL, Identifier, and GitLab single sign-on URL.
• The GitLab metadata URL.

Users then enter this information into the Azure configuration as part of setting up Azure. Currently, the steps to get this information is separate to the rest of the set up process in the documentation.

This MR moves the steps to get this information into the Set up Azure process to provide a smoother user experience where users don't have to move around the page to set up Azure; instead it is all in the same place.

This MR also tries to account for the fact that the GitLab metadata URL is an alternative to the Assertion consumer service URL, Identifier, and GitLab single sign-on URL for many providers. So instead of manually copy and pasting the Assertion consumer service URL, Identifier, and GitLab single sign-on URL values, you give the identity provider the GitLab metadata URL and it populates the fields for you. Not all identity providers have this option and it is difficult to see which providers do. The wording tries to account for this uncertainty.

Assuming this is approved, it will be followed by similar MRs for the Set up Google Workspace, Set up Okta and Set up OneLogin sections. Finally I'll remove this information from the Configure your identity provider section to ensure no duplication.

Related issues

#394767 (closed)

Author's checklist

• Optional. Consider taking the GitLab Technical Writing Fundamentals course.
• Follow the:
  • Documentation process.
  • Documentation guidelines.
  • Style Guide.
• If you're adding or changing the main heading of the page (H1), ensure that the product tier badge is added.
• If you are a GitLab team member, request a review based on:
  • The documentation page's metadata.
  • The associated Technical Writer.

If you are a GitLab team member and only adding documentation, do not add any of the following labels:

• ~"frontend"
• ~"backend"
• ~"type::bug"
• ~"database"

These labels cause the MR to be added to code verification QA issues.

Reviewer's checklist

Documentation-related MRs should be reviewed by a Technical Writer for a non-blocking review, based on Documentation Guidelines and the Style Guide.

If you aren't sure which tech writer to ask, use roulette or ask in the #docs Slack channel.

• If the content requires it, ensure the information is reviewed by a subject matter expert.
• Technical writer review items:
  • Ensure docs metadata is present and up-to-date.
  • Ensure the appropriate labels are added to this MR.
  • Ensure a release milestone is set.
  • If relevant to this MR, ensure content topic type principles are in use, including:
    • The headings should be something you'd do a Google search for. Instead of Default behavior, say something like Default behavior when you close an issue.
    • The headings (other than the page title) should be active. Instead of Configuring GDK, say something like Configure GDK.
    • Any task steps should be written as a numbered list.
    • If the content still needs to be edited for topic types, you can create a follow-up issue with the docs-technical-debt label.
• Review by assigned maintainer, who can always request/require the reviews above. Maintainer's review can occur before or after a technical writer review.