Edits to grouping of validation errors

[robredpath]

See OpenDataServices/cove#1117 for how we did this for 360Giving.

Right now, all of the validation errors are presented in one table. Grouping these by type (eg missing-but-required, format errors, 'other') helps people understand what kind of things they need to do in order to make their data use the standard.

The task here is to:

• Review all possible errors, see if the same groupings as we used for 360 are appropriate (they probably are)
• Implement the splitting up of the errors
• Write simple, appropriate text to frame the errors

[jpmckinney]

Where can I test the dev code? Also, do we have a sample file that triggers as many errors as possible? I'd like to review the grouping as I hadn't been notified on OpenDataServices/cove#1168. For instance, the "Format" group should probably be renamed "Type and Format" because "not a string" (type) is not the same type of error as "not a date" (format). The description text would likely have to be similarly updated.

[robredpath]

@jpmckinney sorry no-one got back to you on this at the time! See my response in OpenDataServices/cove#1180 regarding test data. Could you pull your comments from testing into a list of changes that you'd like to see and we can get it into the pipeline to get worked through?

[jpmckinney]

Some quick feedback from submitting: http://standard.open-contracting.org/review/?source_url=https://raw.githubusercontent.com/OpenDataServices/cove/master/cove_ocds/fixtures/badfile_all_validation_errors.json

1. Collapsing a "Structural Errors" group causes all additional labels (e.g. "Required Fields") to disappear.
2. "Format" should be renamed to "Type and Format", or the errors should be re-grouped into "Type" and "Format" groups (for reasons in https://github.com/OpenDataServices/cove/issues/1159#issuecomment-488037916)
3. "Invalid code found in …" seems to duplicate the "Codelist Errors" group. OpenDataServices/cove#1044
4. There's an opportunity to group "… is too short …" errors into a "Length" group.

[robredpath]

Group validation errors by type

[jpmckinney]

Remaining issues are in this comment: #118 (comment), one of which is repeated in #120