build col spec matching project info response

[the-mad-statter]

This pull request addresses issue 465 where {REDCapR} fails to retrieve project records on older versions of REDCap (~7.3.5).

The root cause of the issue is that older versions of REDCap fail to report all project information expected by {REDCapR}. The most critical missing project information is whether a project uses repeatable instruments or events.

The issue is addressed by:

1. adaptively building a column specification that matches the columns returned by the project information endpoint
2. halting the reading of records with a message in the event of a REDCap failure to report on repeatable instruments or events usage in the project