hmm - removing the links from the quarantine-report e-mail-template can be done - you need to create your own 'spamreport-custom.tt' in '/etc/pmg/templates' (you can take '/var/lib/pmg/templates/spamreport-verbose.tt' as starting point).
However as long as you put a link to the quarantine-interface in the template the user will be able to whitelist/blacklist/... the mail from the web-interface
As said if you remove the above lines users won't be able to click on the action inside the e-mail - they can still click on the link in the bottom - go to the quarantine-webinterface (the link for that is on the bottom of the template) and click those same actions there
The admin can always do those actions - by logging into the regular interface and clicking on Administration->spam quarantine