Make cpEditUrl available in GraphQL

[Wiejeben]

As a service we would want to add an edit button to on our pages, for this we would like to have the ability to get the value from the cpEditUrl function via GraphQL.

[brandonkelly]

This would obviously reveal the CP URL, which may not be desired, so it’s something we’d need to add a new schema setting for, similar to what we do for drafts and revisions, and have it be disabled by default.

[Wiejeben]

Ah I didn’t think about that! Will probably look into extending GraphQL ourselves since our GraphQL queries are handled internally.

[andris-sevcenko]

It shouldn't be too hard if you use https://craftcms.com/docs/3.x/extend/graphql.html#modifying-type-fields

Also, sections are memoized, so there probably won't be a noticeable performance hit, either.