Download and parse OnionPerf analysis .json files instead of .tpf files

With #34070 (moved) and #34072 (moved) being merged and deployed we can now change metrics-web to download and parse OnionPerf analysis .json files instead of .tpf files.

added actualpoints::0.2 component::metrics/statistics owner::karsten priority::medium resolution::implemented severity::normal sponsor::59-must status::closed type::enhancement labels

Trac:
Type: defect to enhancement

Pushed to master as ​​commit 5cdcfc0. Closing.

Trac:
Status: assigned to closed
Resolution: N/A to implemented
Points: N/A to 0.2

Trac:
Actualpoints: N/A to 0.2
Points: 0.2 to N/A

Like #34072 (moved), this was a prerequisite for doing #34141 (moved), which makes this a necessary part of Sponsor 59, too.

Trac:
Sponsor: N/A to Sponsor59-must

closed

added 1h 36m of time spent