A few tricks about setting up a Google external system.

1) When converting a p12 file to the "Service account private key" field, there are accurate instructions for using openssl for the conversion. However, the p12 file has a password on it which everyone needs to search the internet for to find. The password is 'notasecret', and it would be helpful to display that information so it's right there when they are running the command.

2) Also with the private key field, it's not clear whether the `----- BEGIN PRIVATE KEY -----` part is needed, and whether newlines in the value are ok. From testing, NO you don't include the header and footer, and YES newlines are ok

3) The test method searches for a group with id "testFakeGroupId", which fails if the service account does not have a scope for reading groups, even if the connection is successful. The info could use some documentation around that.