Use Firefox's Tracking Protection as a means for performance improvements

When improving browser performance one of the low-hanging fruits we could think about is using at least some of the Enhanced Tracking Protection (ETP) feature for that purpose. This ticket is the parent ticket to track all the involved work.

There are a number of questions involved that we need to discuss and decide how to proceed (and probably more than I came up with below):

a) Do we want to use the same message and UI of ETP as it is shipped right now in Firefox?

b) Do we want to enable the same lists as Mozilla is doing in the respective browsing modes?

c) Do we want to use the same list retrieval mechanism as Mozilla (using the safebrowsing protocol)?

d) Do we want to host the tracking protection lists ourselves?

e) Does the work in this ticket (and child tickets) is our answer to "ship an ad blocker" in Tor Browser? Or do we feel the need to still ship another blocking tool on top of ETP?