Update Lantern test trace database

[connorjclark]

We last updated this in 2019, and so all of our Lantern simulation changes are operating on traces that are quite old.

We can no longer utilize WPT due to API constraints (no real mobile device over the API), so the new collection method needs to be done all locally.

• Drop sampling misc(lantern-collect): drop sampling #15072
• Design and document new collection method
• Collect the new traces
• Use receiveHeadersStart added from core(time-to-first-byte): use receiveHeadersStart #15126 in network-analyzer.js
• update + land core(network-request): exclude dns from rtt estimates #15110