Populate score without mods during ongoing imports & add command for backpopulation of it on existing scores

[bdach]

• End goal is Classic mod multiplier needs reconsidering osu#27685.
• Depends on Read & store score total without mods on submission osu-web#11211
• Depends on Compute total score without mods during standardised score conversion osu#28277
• Submission should be turned off on old clients that don't send total score without mods before running the command here

This PR ensures that the legacy score watchers populate total_score_without_mods correctly to the json (to match ppy/osu-web#11211), and also features a command to fill in that data wherever it's missing, using an approximate estimate.

Only tested locally on a small scores table, so buyer beware.

[peppy]

Just a self heads-up that this still needs to be run at some point, with consideration given to table size expansion when it is.