different time frames for pre calculated indicators

[AlexTheLion123]

Summary

• There may be a use case where a user wants to create an indicator that uses a time frame that is different from the loaded candles

Acceptance criteria

• [ ] User should be able to create indicator with custom time frame, like so:

indicators.add(
      "ema_4h",
      pandas_ta.ema,
      {"length": 10},
      IndicatorSource.close_price,
      time_bucket=TimeBucket.h4,
  )