Documentation for Graph API permissions

Problem/Motivation

The README documentation includes the following in Section 7:
Click on "Add a permission", select "Microsoft Graph", and then choose the type of permissions your app requires (for SharePoint Online, "Sites.ReadWrite.All" under "Application permissions" should suffice).

Our SharePoint admin was unhappy about Drupal being able to write to any Sharepoint site, so we used the Sites.Selected permission to restrict access to one specific Site. This works fine.

But it might he helpful for future users to know they can use the Sites.Selected permission for security reasons to restrict access to a specific SharePoint site.

Steps to reproduce

As above

Proposed resolution

Update README documentation for section "7. Set permissions for the Graph API" from:

- Click on "API permissions" in the sidebar.
- Click on "Add a permission", select "Microsoft Graph", and then choose the type of permissions your app requires (for SharePoint Online, "Sites.ReadWrite.All" under "Application permissions" should suffice).
- Click "Add permissions" to save your changes.
- Finally, grant admin consent for the permissions (if required by your organization).

To:

- Click on "API permissions" in the sidebar.
- Click on "Add a permission", select "Microsoft Graph", and then choose the type of permissions your app requires (for SharePoint Online, "Sites.ReadWrite.All" under "Application permissions" should suffice. Use the Sites.Selected permission to restrict access to a specific Site).
- Click "Add permissions" to save your changes.
- Finally, grant admin consent for the permissions (if required by your organization).

Remaining tasks

None

User interface changes

None

API changes

None

Data model changes

None