Interpolate functionality and InterpolationTest.#1323

pierrepetersmeier wants to merge 5 commits intodevie3-institute/PowerSystemDataModel:devfrom

1304-consider-none-equivalent-value-for-missing-data-points-in-weather-sql-versionie3-institute/PowerSystemDataModel:1304-consider-none-equivalent-value-for-missing-data-points-in-weather-sql-versionCopy head branch name to clipboard