Allow dynamic outlier filters to be used with batch LS estimator
Currently, Orekit batch LS architecture does not allow dynamic outlier filter to be used for measurement rejection. Only "static" outlier filters can be used. However, it can be useful to change rejection threshold between iterations.
A second idea related to that issue: having an independent interface for outlier filters could improve code readability. Especially by differentiating measurement value modifiers and measurement status modifier.