The counter implementaiton is now list based, and will not invalidate
previous hits by removing them but by testing if they are within the 1
second span, allowing better integration with replays and spectators.

- Remove '#nullable disable' in KeysPerSecondCalculator and
  KeysPerSecondCounter
- Remove KeysPerSecondCalculator IDisposable implementation
- Make KeysPerSecondCalculator static instance initialized once by
  KeysPerSecondCounters
- Auto transfer dependencies from KeysPerSecondCounter to
  KeysPerSecondCalculator using Resolved properties
- Add internal reset logic to KeysPerSecondCalculator and make it
  independent from Player
- Use GameplayClock.TrueGameplayRate to get real-time rate. If 0 then it
  defaults to the last non 0 rate if no such mod is enabled

gathering

KPS Calculator now uses DI to retrieve the clocks. Using `HUDOverlay` it
is now cached for `KeysPerSecondCounter`s to resolve it. This also
allows to make an "Attach" flow like `KeyCounter`.

…t can be found

`KeysPerSecondCounter` now depends on `KeysPerSecondCalculator` via the
`BackgroundDependencyLoaderAttribute` method, making it appear only in a
gameplay context without requiring `GameplayClock` without using it.

Created private mock classes to use them in place of `GameplayClock` and
`DrawableRuleset`.

…ayer`

This prevents messing with *future* Skin (de)serialization

…s to add timestamps

- Remove null-forgiving operator usages
- Fix code quality issues mentionned by NVika