Institutional managers can't create books but can edit pages

[SteelWagstaff]

When the network has turned off the ability for registered users to create and clone new books, institutional managers are prevented from creating new books (they can still clone books). This should not happen -- institutional managers should always be able to create new books.

In addition, while institutional managers cannot see the pages menu at the root site, when they visit these sites as a logged in user, they do see the 'Edit' button. When they click the edit button, they are able to edit these pages on the root site. This is not desired behaviour. Institutional managers should not be able to create or edit pages on the root site.

This issue was reported by a network manager for the Universities of Wisconsin shared network. See video for demonstration: https://us02web.zoom.us/clips/share/BGNhMDEWWXczOUZFdjRSXy1QalJFSXJMalp6QQE. You can use my steeltest account there to test/confirm, if needed.

Desired behaviour:

1. Institutional managers should still be able to create and clone new books (just like network managers and super admins), even when the 'allow registered users to create and clone new books' setting is turned off for a network
2. Institutional managers should not see an edit button on root site pages, or if they do, they should not be able to edit root site pages after clicking it.

[cmurtagh]

Hey team! Please add your planning poker estimate with Zenhub @arzola @fdalcin @ho-man-chan @MichelleWeremczuk @richard015ar @tw77

[SteelWagstaff]

To test:

1. Go to Network Options -> Book & User Registration Settings and uncheck the 'Allow registered users to create and clone new books' option
2. Log in as an institutional manager and click the 'Create Book' link in the top nav bar. Observe that you can now create new books
3. Attempt to visit the pages menu on the root site or edit one of the pages. Observe that you see a 'you do not have permission' message
4. Visit a page on the root site as a logged in institutional manager. Observe that the edit button is no longer visible at the bottom of the page.
5. Visit the organize page on any book assigned to your institution and edit a chapter. Observe that you can still edit content in books that belong to your institution.
6. Visit a chapter in a book belonging to your institution for which you do not have a role explicitly assigned while a logged in institutional manager. Observe the edit button at the top of the page. Click it. It should work.

[tw77]

Working as expected on dev, ready for release