Add sediment thickness data

Migrate gulf data (csv, geojson) from nshmp-ws to site-data.

Supports use of Martin Chapman's gulf coast GMM.

mentioned in issue ghsc/nshmp/nshmp-lib#125 (closed)

@olboyd

changed milestone to %Coding 'til Christmas

removed milestone %Coding 'til Christmas

added 2023 label

changed milestone to %NSHM Hazard Tool Launch - 2

mentioned in merge request !26 (merged)

!26 (merged) needs to be broken into modifications to site-sdata/basin for tagged 2018 version to be consistent with updates to how site-data is handled in nshmp-lib

closed with merge request !26 (merged)

Not sure how !26 (merged) was merged. Reopening.

reopened

zSed data ready in !28 (closed)
Removing from milestone.
Will merge/close once conus-2018 tagged/approved.

removed milestone %NSHM Hazard Tool Launch - 2

Complete

closed