[SCT-EAD]: Extend the summary to include information on erosion

[trietmnj]

g) Extend the NSI summary to include information on erosion. For each value of reach, occupancy type, damage category, and social vulnerability status (SV; i.e. in or outside an SV zone), summarize the count of NSI points and statistical sum, mean, min/max range, and quartile information of structure/contents value in and outside erosion zones. The structure and contents value should be available from the NSI data.

[g-braide]

Add erosion column to sv export and should be optional