Add support for digital calibration reports

[jborbely]

I think the <report> element is one way to digitise paper-based reports so that calibration data may be easily read and then used in analysis software. It adds complexity to the equipment register because it tries to solve a historically (and still current) complex problem. The equipment register becomes simple once digital calibration reports are embraced.

I propose that the <component> element supports a xsd:choice between the past (analog) or the future (digital) reporting styles

<xsd:choice>
    <xsd:element name="paper" type="analog">
        <xsd:annotation>
            <xsd:documentation>
                A custom MSL way to digitise paper based reports.
                The child element is another xsd:choice of either a file, equation, serialised, table, ...
            </xsd:documentation>
        </xsd:annotation>
    </xsd:element>
    <xsd:element name="dcc" type="digital">
        <xsd:annotation>
            <xsd:documentation>
                A digital calibration certificate in an internationally accepted standard format.
            </xsd:documentation>
        </xsd:annotation>
    </xsd:element>
</xsd:choice>

where, only two pieces of information are required in the digital case

• URI (where the report is located: in the cloud, network drive, ...)
• checksum (since it cannot be embedded in the digital report)

  <xsd:complexType name="digital">
  <xsd:sequence>
      <xsd:element name="uri" type="xsd:anyURI">
          <xsd:annotation>
              <xsd:documentation>
                  Where the report is located.
              </xsd:documentation>
          </xsd:annotation>
      </xsd:element>
      <xsd:element name="sha256">
          <xsd:annotation>
              <xsd:documentation>
                  The SHA-256 checksum of the report.
              </xsd:documentation>
          </xsd:annotation>
          <xsd:simpleType>
              <xsd:restriction base="xsd:string">
                  <xsd:pattern value="[a-fA-F0-9]{64}"/>
              </xsd:restriction>
          </xsd:simpleType>
      </xsd:element>
  </xsd:sequence>
  </xsd:complexType>

  An equipment register becomes a historical record of simple <dcc> elements and is the centralised way for software to access the entire history of the equipment.

Today, equipment registers contain only <paper> elements. In a few (optimistically) years, a mixture of <paper> and <dcc>. Eventually, only <dcc>.

Note: The names of tags specified above are not important at this stage.

[jborbely]

Added in 931abaec0423e5d3e25ce355ca5f1132b261f6e2, example usage

<digitalReport format="MSL PDF/A-3">
  <url>file://msl-nas/Photometry/Calibrations/neutral_density_filters.pdf</url>
  <sha256>8392e473a047543773138653b98037956fa2086e4a54fc882d913f10cc217728</sha256>
</digitalReport>