[education] add documentation for configuring Blackboard LMS

[scollovati]

Why:

Closes: https://github.com/orgs/community/discussions/44066

What's being changed (if available, include any code snippets, screenshots, or gifs):

This PR adds documentation for properly configuring the GitHub Classroom integration with Anthology Blackboard LMS. This LMS is fully compliant with [LTI1.3 Advantage](https://site.imsglobal.org/certifications/anthology/blackboard-learn), particularly the NRPS service used by GitHub Classroom for roster synchronization.

If this PR is accepted, we suggest the following improvements:

1. Add “Blackboard” as an LMS option in the dropdown menu on the registration page (https://classroom.github.com/register-lms).
2. Change “Other” to “Blackboard” in the relevant code section (step #3 in register-a-learning-management-system-with-github-classroom.md).

Important note: The optimal integration method for GitHub Classroom into Blackboard would involve GitHub managing a global registration in the Anthology Developer Portal (step #1 in register-a-learning-management-system-with-github-classroom.md). This approach is recommended by [Anthology](https://docs.anthology.com/docs/blackboard/lti/1.3/best-practices#why-vendor-tool-registration-is-best), as it allows each institutional deployment to be distinguished by its deploymentId and platform URL. However, deploymentId is not currently a configurable field on https://classroom.github.com/register-lms. Therefore, the registration flow proposed in this PR, which creates a unique clientId for each institution, is currently the only feasible option.

Check off the following:

• I have reviewed my changes in staging, available via the View deployment link in this PR's timeline (this link will be available after opening the PR).

  • For content changes, you will also see an automatically generated comment with links directly to pages you've modified. The comment won't appear if your PR only edits files in the data directory.

• For content changes, I have completed the self-review checklist.

[welcome]

Thanks for opening this pull request! A GitHub docs team member should be by to give feedback soon. In the meantime, please check out the contributing guidelines.

[github-actions]

Automatically generated comment ℹ️

This comment is automatically generated and will be overwritten every time changes are committed to this branch.

The table contains an overview of files in the content directory that have been changed in this pull request. It's provided to make it easy to review your changes on the staging site. Please note that changes to the data directory will not show up in this table.

---

Content directory changes

You may find it useful to copy this table into the pull request summary. There you can edit it to share links to important articles or changes and to give a high-level overview of how the changes in your pull request support the overall goals of the pull request.

Source	Preview	Production	What Changed
education/manage-coursework-with-github-classroom/teach-with-github-classroom/connect-a-learning-management-system-course-to-a-classroom.md	fpt	fpt
education/manage-coursework-with-github-classroom/teach-with-github-classroom/register-a-learning-management-system-with-github-classroom.md	fpt	fpt

---

fpt: Free, Pro, Team
ghec: GitHub Enterprise Cloud
ghes: GitHub Enterprise Server

[nguyenalex836]

@scollovati Thanks so much for opening a PR! I'll get this triaged for review ✨

[github-actions]

Thanks for opening a pull request! We've triaged this issue for technical review by a subject matter expert 👀

[github-actions]

A stale label has been added to this pull request because it has been open 7 days with no activity. To keep this PR open, add a comment or push a commit within 3 days.

[scollovati]

@scollovati Thanks so much for opening a PR! I'll get this triaged for review ✨

@nguyenalex836 may I help in finding a SME to review this?

[nguyenalex836]

@scollovati That's very kind of you! Our internal SME team is actually reviewing this now. Once they have an update to provide, we will post here 💛

[github-actions]

A stale label has been added to this pull request because it has been open 7 days with no activity. To keep this PR open, add a comment or push a commit within 3 days.