Component-wise DM correction

[DanielaBreitman]

Problem: Certain multi-component bursts seem to have components with different DMs. It would be useful to add a feature to correct DM for every component separately. I think this feature can only work when there is some space around each component. If the components are too close to one another, this may be more tricky. I think it should be like a on/off feature (off by default) that someone can turn on if they notice the DMs are different and the pulses are far enough apart.

Example: Event 65547659 (see image)

Fitburst file location:/data/user-data/danielabreitman/fitburst_65547659.npz on frb-analysis.