deprecate type slot

[wdduncan]

During the January release, we encountered problems due the type slot not have a value.

Kitware reads the values of the type slot when populating the the postgres tables. The type slot is also required for change sheets to work.

So, make the type slot required.

Also, create enums to constrain the range of the type slot.

cc @dehays @turbomam @sujaypatil96

[wdduncan]

Think about this a bit ... we could use the pattern attribute to constrain the values.

[wdduncan]

Per meeting today:
We are not going to require slots, but we should create enums for the range of the type slot.

[wdduncan]

mistakenly closed

[wdduncan]

After discussing this more with @dehays, we think it is best to deprecate the type slot. The reason is there is inconsistent usage and confusion about what the values should be.

Originally, the type slot was used to capture the information about the python class used to create the instance data. This allowed me to reference the type of python object that was used to create a JSON record.

When a linkml schema (such as the nmdc-schema) is converted into python, the linkml class names are convert into python classes with named changed into PascalCase and prefixed with nmdc. For example, the nom analysis activity class in the nmdc-schema is converted into NomAnalysisActivity in the nmdc.py file. In the type field, this is class is then represented as nmdc:NomAnalyisActivity in order to make it explicit that the class comes from the nmdc namespace. However, this usage seems to be causing confusion.