Proposal for fixed attribute types and "long names"

[mumbricht]

This is related to issue #646

ReqIF requires fixed types for attributes. This makes sense, as a particular attribute should describe the same thing across items. For example, given a "tested" attribute, it is not appropriate to switch from bool (False) to date (date of test). A new "test_date" attribute should be created which is empty if "tested" is false. Or any of a number of other logical implementations.

I propose that in the .doorstop.yml document a second and third dict attribute called default_types and default_long_names in order to store this data and permit for error checking and tooltips respectively. The keys would match the keys for defaults

I have written get_or_gen() function for ReqIF functionality which can be used to populate these dicts automatically or by prompt. Tests are in core/tests/test_editor.py.

I would appreciate feedback, since this is a pretty deep change to the document structure. In the meantime, I can guess at the datatypes and throw in case of inconsistency. This is going to make issues though, since .yml is known to make unexpected typing decisions.