[DAR-2973][External] Creation and import of text item-level properties

[JBWilkie]

Problem

darwin-py does not have the ability to:

• Create missing text-item level properties from the properties manifest file
• Import text item-property values

Solution

• Add the above capabilities
• We also remove the ability to create any property (item, annotation, or section) from annotations alone. Properties may only be created from the manifest file, since otherwise we'd need to make an assumption about what type of property we are creating

Changelog

Import of text item-level properties

[linear]

DAR-2973 Add support of arbitrary text properties to darwin-py