[Feature Request]: Rework Propensity Score Adjustments

[SvenKlaassen]

Describe the feature you want to propose or implement

I think it might be a good choice to rework

• ipw_normalization
• trimming_rule
• trimming_threshold

The goals would be to generalize reweighting schemes and other adjustments.
If possible this should include the in_sample_normalization option of the doubleml.did module.

Propose a possible solution or implementation

• Include several functions in utils._propensity_score
• Rename trimming to clipping

Comments, context or references

Helpful resources:

• Adaptive normalization for IPW estimation