docs: remove prioritization section

Source code: :func:`sbws.core.scanner.run_speedtest`

Simple relay prioritization

~~~~~~~~~~~~~~~~~~~~~~~~~~~

This may be the most complex part of sbws.

Sbws makes an effort to prioritize measurements of relays that don't have many

recent results. For example: relays that just joined the Tor network or relays

that haven't been online in the past few days. This goal is achieved using a

min-priority queue and the concept of *freshness*.

Freshness is defined as the amount of time between when the measurement was

made and the time sbws will stop considering it valid. Thus, a measurement made

more recently will have more time until it is no longer valid (higher

freshness) and a measurement made a long time ago will have very little time

until it is no longer valid (lower freshness).

Over time, sbws will make many measurements for a given relay. The sum of these

measurements' freshnesses is the relay's priority. As we are prioritizing like

a min-priority queue, a higher sum of freshnesses means *worse* priority while

a lower sum of freshnesses means *better* priority.

  Example: AlphaRelay33 joined the network yesterday and sbws has measured it

  once so far. BetaRelay87 has been in the network for years and has been

  getting measured regularly approximately once a day. BetaRelay87 has five

  measurements that are still valid, with freshnesses 10, 100, 500, 1000, and

  1500. AlphaRelay33's one measurement has freshness 3000. Because the sum of

  BetaRelay87's 5 measurements is greater than AlphaRelay33's one measurement,

  AlphaRelay33 has *better* priority and will be measured next before

  BetaRelay87.

  Example: AlphaRelay33 is still a brand new relay with its one measurement

  in the last day with freshness 3000. CharlieRelay9 has been in the network

  for a long time, but had technical issues last week and hasn't been online in

  many days. When CharlieRelay9's operator finally gets him back online, he

  still has one valid measurement with freshness 10. Because AlphaRelay33's

  measurement is fresher, CharlieRelay9 has *better* priority and will get

  measured first.

Sometimes measurements fail. Hopefully they fail because of transient issues,

and with that hope in mind, it would be nice if a relay with a failed

measurement didn't have to wait a long time to have another chance at a

successful measurement. For this reason, when summing the freshnesses of

results for a given relay, sbws will artificially *reduce* the freshness for

measurements that were not successful. This makes the sum of freshnesses lower

for that relay, and therefore the priority *better* so it can be measured again

sooner.

Simple result storage

~~~~~~~~~~~~~~~~~~~~~