Update information on using the dev VM with the VPN
Update information on using the dev VM with the VPN

This commit updates the section on issues between the developer VM and the VPN. It removes the old VPN details and adds information about bypassing NFS.
alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs