Feat: Delete Peak button

[Radascript]

• IMPORTANT: only works if select_peak(), b_click() and dashboard() are included directly in the notebook. When exact copies are only loaded from the viz.py script, removing peak does not work.
• IMPORTANT: the b_click() has a really yucky issue: raw_data_dict and dash_p variables are hard coded and they are environment dependent... That's really bad. I need to figure out how to pass parameters to the event bound to the button!
• Refactor: Dashboard / Delete button very not DRY code moment. currently I literally reuse same code in parts of dashboard() and b_click() functions. Obv need to be moved into its own function but it's a little annoying.
• Enhancement: Would be nice to add a message below Delete button saying smth like "Peak 80042 for MU 0 has been deleted."
• Enhancement: Would be nice to add ctrl+Z functionality to un-delete