[BUG] Sub-element SpecsFile in MMApp JSON does not respect XSD definition

[remytorro]

Describe the bug
MMApp allows to define a SpecsFile (often an url link) for each hardware object. This makes sense since most objects inherit from ManufacturerSpecs which enables a SpecsFile sub-element. The problem we encounter is that when writing an MMApp config defining a SpecsFile we end up with the following JSON:

{
            "Name": "Zeiss 43 em",
            "ID": "858a5b4f-918c-4327-bce6-8a6f9e39e310",
            "Tier": 1,
            "Schema_ID": "EmissionFilter.json",
            ...,
            "Manufacturer": "Zeiss",
            "SpecsFile": "https://www.micro-shop.zeiss.com/en/us/shop/filterAssistant/filtersets/000000-1114-101",
            "CatalogNumber": "000000-1114-101",
            ...,
},

where SpecsFile is associated with a string value. The XSD defines SpecsFile as something much more complicated (a FileAnnotation):

<xsd:complexType name="ManufacturerSpec">
  ...
  <xsd:sequence>
    <xsd:element maxOccurs="unbounded" minOccurs="0" ref="MapAnnotation"/>
    <xsd:element minOccurs="0" name="SpecsFile" type="FileAnnotation">
    ...
</xsd:complexType>

which is itself a TypeAnnotation (and itself Annotation and so on):

<xsd:complexType name="TypeAnnotation">
  ...
  <xsd:complexContent>
    <xsd:extension base="Annotation"/>
  </xsd:complexContent>
</xsd:complexType>
<xsd:complexType name="Annotation">
  ...
  <xsd:sequence>
    <xsd:element name="Description" minOccurs="0" maxOccurs="1">
      ...
      <xsd:simpleType>
        <xsd:restriction base="xsd:string">
          <xsd:whiteSpace value="preserve"/>
        </xsd:restriction>
      </xsd:simpleType>
    </xsd:element>
    <xsd:sequence>
      <xsd:element ref="AnnotationRef" minOccurs="0" maxOccurs="unbounded">
        ...
      </xsd:element>
    </xsd:sequence>
  </xsd:sequence>
  <xsd:attribute name="ID" use="required" type="AnnotationID">
    ...
  </xsd:attribute>
  <xsd:attribute name="Namespace" use="required" type="xsd:anyURI">
    ...
  </xsd:attribute>
  <xsd:attribute name="Annotator" use="optional" type="ExperimenterID">
    ...
  </xsd:attribute>
</xsd:complexType>

I'm not sure it would be wise to adapt MMApp in that regard, perhaps it is the XSD definition that should be simplified for SpecsFile.

A typical problem we encounter is that it is currently hard to "understand" SpecsFile is a sub-element and even harder to put the URL in its proper place. A nested structure (list of dict - typical of sub-elements) in the JSON config could help.

From our understanding, a SpecsFile object would look like this in xml:

<SpecsFile ID="Annotation:YourID" Namespace="YourNamespace">
    <BinaryFile FileName="original_name.pdf" Size="0">
        <External href="https://lumencor.com/products/sola-light-engine/" SHA1="0000000000000000000000000000000000000000"/>
    </BinaryFile>
</SpecsFile>

A JSON structure that would be easier for us would be something like this:

{
    "Name": "Zeiss 43 em",
    "ID": "858a5b4f-918c-4327-bce6-8a6f9e39e310",
    "Tier": 1,
    "Schema_ID": "EmissionFilter.json",
    "Manufacturer": "Zeiss",
    "SpecsFile": [
                    {"ID": "some-id",
                     "Namespace": "some namespace",
                     "BinaryFile": [
                                    {"FileName": "some file name",
                                     "Size": "0",
                                     "External": [
                                                    {"href": "https://www.micro-shop.zeiss.com/en/us/shop/filterAssistant/filtersets/000000-1114-101",
                                                     "SHA1":"00000000000000000001"}
                                                 ]
                                    }
                                  ]
                    }
                ]
}