TimeSeries of Scoreboards and Scores

[ppanopticon]

The now removed ScoreboardUpdateable kept in-memory time-series of a Scoreboard's state. If we need this mechanism in the future, then this needs to be replaced.

I would suggest, that we decouple this entirely from the existing RunManager facilities, using the following design goals:

• The facility that records these time series is a standalone class and generates snapshots of all the active RunManagers.
• Snapshots should be taken at a regular, be it configurable, time interval instead of every time there is a change to a scoreboard. This should happen in a separate, low-priority thread.
• Time series could actually be recorded to disk, so that memory pressure doesn't build-up over time.
• It should probably be an opt-in feature.

[lucaro]

I've implemented a PoC of a new mechanism built upon the event stream in 9f6a44c.