Add method to all geochemistry schemas

Add method attribute to all geochemistry schemas:

"Method": {
          "type": "string",
          "description": "The sample analysis method used for this analysis"
      }

@michael_jones_epam can confirm the correct pattern required to allow values only from the SampleAnalysis reference data.

Draft Reference List: https://gitlab.opengroup.org/osdu/subcommittees/data-def/projects/RAFSDDMSDEV/docs/-/blob/main/Design%20Documents/ReferenceValues/Manifests/reference-data/OPEN/GeochemistryMethod.json

Edited by Michael Jones