We recently switched to downloading .tpf files from OnionPerf hosts,
and we ran out of functioning Torperf hosts, so let's remove the code
for downloading and merging Torperf files.  Part of #21272.

Implements #21272.

Implements #21535.

Fixes #21443.

Use try-with-resources to prevent this.

Implements task-21195.

Fixes #21143.

added executable bootstrap script, removed metrics_checks.xml.

Adapted from Onionoo's #20712.

This test currently breaks and will be fixed in #20714.

Some bridges report these hidserv-* lines, probably shortly after
switching from relay to bridge mode.  There's nothing particular
sensitive in these lines that would reveal the bridge IP address or
location.  We can simply copy them over like the other statistics
lines.

Fixes #20714.

as it is not part of the webapp files.
Adapted path in INSTALL.md to match the new location.

Contains many suggestions by iwakeh.

Implements #20380.

by grouping them according to marker and host.

Implements task-19831.

these temporary files after sync.