Add entrypoint for E-Field

Entrypoint should support two data types: variation - 1Hz, 1min adjusted - 1Hz, 1min (after the data has been adjusted with -1*identity)

added New Feature label

assigned to @pcain

changed milestone to %Miniseed Webservice

removed milestone %Miniseed Webservice

changed milestone to %Miniseed Pipeline

added In Progress label

added Needs Review label and removed In Progress label

mentioned in merge request !149 (merged)

added In Review label and removed Needs Review label

mentioned in commit 60d89c27

closed with merge request !149 (merged)

removed In Review label