Schedule removal of deprecated features #152
Description
I think it is safe to start removing support for frames and a few other actions (e.g. codemeta) that were not commonly used. The documentation has been updated in the v2.3 release to indicate that the feature has been deprecated. With the frame support this has been superseded by SQL query support. The codemeta verb to update/replace the codemeta.json file for the collection is superseded by CMTools support for managing codemeta.json files. The check/repair actions do not support SQLstore collections which are now the default. It makes sense to also remove that code as a step to phase out storing JSON documents in a pairtree.
Cutting the code now should not impact our primary use case for dataset (feeds v1.6). It lays the ground work for a smoother transition to v3 when planning is complete.