Store total score without mod multipliers to local database and to replays, and send it on score submission

[bdach]

RFC. This is supposed to be the start of a series of changes which is an alternative to #27816, and will generally facilitate unconstrained mod multiplier rebalancing without worry of precision or even complete total score loss in the future.

I will continue with further changes if this is accepted, but I generally will not be PRing further changes until I see agreement on this general direction.

General plan

The plan here is as follows:

1. Ensure the client stores and sends the score without mod multipliers.
2. Ensure osu-web reads the score without mod multipliers, and stores it. (Up in the air as to exactly how - either new column or in the json blob; new column will require table rebuild, json blob will not but may behave erratically wrt storage requirements. I have a branch that implements the json blob variant.)
3. After (2) is deployed, write a osu-queue-score-statistics command that will back-populate the pre-mod multiplier total score for rows that do not have it.
4. Turn off score submission for client versions that are not sending information from (1).
5. After all of the above, mod multipliers can be arbitrarily rebalanced using another osu-queue-score-statistics command forevermore.

Client considerations

• Scores already in the database will receive the pre-mod multiplier score via the realm migration. This means that it will run synchronously on startup, but I'm not sure I'm particularly worried about that (migration took ~350ms on a local database with ~7k scores inside).
• Scores set after this change will have the new property populated as part of the standard operation of Player.
• Scores imported from stable replays will have the new property populated via the standardised score migration flow.
• Scores imported from lazer replays recorded after this change will read the new property from the replay.
• Scores imported from lazer replays recorded before this change but after LegacyReplaySoloScoreInfo was created will have the new property populated inline via a crude estimation.
• Scores imported from lazer replays recorded before LegacyReplaySoloScoreInfo existed are considered obsolete and unsupported. They will receive a TotalScoreWithoutMods of zero, which means that their total score will likely also zero upon future rebalances.
• No effort is made to account for past mod multiplier changes. If a replay was set back before ranked play went live and there were some wacky in-flux multipliers active back then, this does nothing to attempt to fix or even detect that.

[peppy]

@bdach i see no reason not to go ahead with this and get it in sooner rather than later. good to move out of draft?

[bdach]

If you're ok with the plan as outlined in the OP then I see no reason not to.

[peppy]

If you're ok with the plan as outlined in the OP then I see no reason not to.

Apart from storage concerns I believe it sounds fine. And even if not, this initial step can cause no harm (and at very least help with locally saved scores).