This updates LinkedIn connector to use the more recent v2 APIs. Necessary because v1 APIs are not able to retrieve email ids any more with the default permissions.

The API URLs are now different. Fetching the email address is now a separate call, made after fetching the profile details. The `r_basicprofile` permission is not needed any more, and `r_liteprofile` (which seems to be the one assigned by default) is sufficient.

The relevant API specifications are at:
- https://docs.microsoft.com/en-us/linkedin/shared/integrations/people/profile-api
- https://docs.microsoft.com/en-us/linkedin/shared/integrations/people/primary-contact-api
- https://docs.microsoft.com/en-us/linkedin/consumer/integrations/self-serve/migration-faq#how-do-i-retrieve-the-members-email-address