Since when a destination fails, all the threads using it will also
fail that moment.
For now not checking which threads are actually using it.
Also lower the time to retry.

Closes: #29891.

calling requests.get, since RequestException does not catch all.

The number of prioritized relays was set to the minimum, but in a
small testing network this could be lesser than the number of
relays in the network.

measuring unique relays.
Create new module heartbeat.

Closes: #28652

There was an ammended commit diverging from canonical master

Conflicts:
	sbws/lib/v3bwfile.py
	tests/unit/lib/test_v3bwfile.py

in the bandwidth file to know why there excluded relays.
The excluded relays' lines do not have the `bw` KeyValue so that
Tor does not parse them nor include them in a vote.

Closes: #28563

to the bandwidth file header.

Closes: #28983.

and improve a bit the summary about what sbws does.
Closes: #29722

Part of #28565.

Part of #28565.

and return reason why the relay was excluded to be able to count
the relays excluded in the header.
Part of #28565.

Part of #28565.

if sbws is shutting down.

for the maximum number of failures before the destination is
not functional.

Part of #29589.

Closes: #29589.

Part of #29589.

Part of #28565.

Part of #28565.

and return reason why the relay was excluded to be able to count
the relays excluded in the header.
Part of #28565.

Part of #28565.

because the http server is not concurrent/asynchronous and there
are as many processes as tox environments querying the http server.

It was forgotten in #28566

Closes: #28567

and priority list counters

Part of #28567.

Part of #28567.

Part of #28567.

about the number of times it was in a priority list.
Part of #28567.

Part of #28567.