Pro 8152 add external front

[BoDonkey]

Summary

Summarize the changes briefly, including which issue/ticket this resolves. If it closes an existing Github issue, include "Closes #[issue number]"
This PR adds annotateWidgetForExternalFront() methods to the two modules. This allows the anchors budle to be used in an Astro project without custom code. It depends on changes in core and the @apostrophecms/apostrophe-astro module. Closes PRO-8152

What are the specific steps to test this change?

For example:

1. Run the website and log in as an admin
2. Open a piece manager modal and select several pieces
3. Click the "Archive" button on the top left of the manager and confirm that it should proceed
4. Check that all pieces have been archived properly

1. Create a new project from starter-kit-astro-essentials
2. Link in the pro-8152-anchors branches of both core and @apostrophecms/apostrophe-astro in the backend and frontend portions of the project, respectively.
3. Install this module in the backend.
4. Add an image widget in any area, edit to add an anchor. Check the code for the addition.
5. Add a rich-text widget, confirm lack of anchor ID field.
6. change the image widget options on the backend, adding an anchorAttribute option. Confirm the attribute changes in the markup.

What kind of change does this PR introduce?

(Check at least one)

• Bug fix
• New feature
• Refactor
• Documentation
• Build-related changes
• Other

Make sure the PR fulfills these requirements:

• It includes a) the existing issue ID being resolved, b) a convincing reason for adding this feature, or c) a clear description of the bug it resolves
• The changelog is updated
• Related documentation has been updated
• Related tests have been updated

If adding a new feature without an already open issue, it's best to open a feature request issue first and wait for approval before working on it.

Other information:

[linear]

PRO-8152 As an Astro developer I can use our anchors module without custom code at project level

[boutell]

Seems fine but mongodb 6 is also dead now.

[boutell]

nice.