[#65806948] Actually include sudoers.d
[#65806948] Actually include sudoers.d

The line to include sudoers files from /etc/sudoers.d is in the stock
Ubuntu /etc/sudoers, but wasn't in our GOV.UK sudoers file.

The changes in 1c33184cac723b061642857c041825295fe9437a rely on
sudoers.d, so include that directory in this commit.

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet