The CIM science package has been made too vanilla

[bnlawrence]

The existing science package was changed in early 2017 to remove anything with semantic meaning with respect to the scientific description of a model. It now depends on specialisations to have any meaning. In order to put some utility back, we should create some new classes which specialise these vanilla classes and can be used by any tools that don't want to use a specific specialisation. These would not be needed for any CMIP6 application, but would be targeted to application for any other simulation description.

[bnlawrence]

At the same time, the documentation strings should be changed to not be so dependent on the presence of a specialisation.

[bnlawrence]

We could consider putting these in as an "exemplar specialisation" into the CIM package itself.

[bnlawrence]

Example:

• domain requirement now has a required resolution which is a science topic, which works fine with CMIP5 specialisations, but isn't the right answer for other applications.