treat DO_NOT_TRACK=1 as NEXT_TELEMETRY_DISABLED=1

[unhammer]

Goals

1. make it easy for people who want telemetry off when developing stuff to turn telemetry off whether they're using brew or gatsby or azure or whatever
2. be nice
3. do the right thing

Non-Goals

1. world peace
2. ending hunger
3. anything other than disabling telemetry without making people dig for docs

Background

https://consoledonottrack.com/

Proposal

Implement DO_NOT_TRACK=1 in whateve rway NEXT_TELEMETRY_DISABLED=1 is implemented. Should be a ridiculously simple change for whoever implemented that, once the bikeshedding dust has settled.