Expose optional JSON table schema fields

[Floppy]

JSON Table Schema defines the following optional fields:

• type
• title
• description
• format

If Csvlint::Schema could expose those, I can show them in the UI.

[ldodds]

We've added support for type but as a field within constraint which differs from the current spec. So that's in there already, although slightly differently to the JTS spec

The format keyword in JTS might end up getting deprecated too, in favour of a separate pattern and datePattern fields. We have pattern implemented.

I'm going to be working on a PR to tweak the JSON Table Schema spec to encompass those changes. Should help us align with that for now.

We should definitely add title & description for fields though.

We could also do the same at the schema level. JTS doesn't have anything at that level, but the structure could be extended without clashing. Would let people include some basic metadata. Maybe we should make a separate proposal for that. Data Package could also reference the schema via a URL (currently its only in-line).

[Floppy]

OK, I'll back out the format and type fields in the UI - I was thinking they would be part of constraints anyway.

[ldodds]

I think we now expose everything (datePattern) went in earlier, going to close this for now. We can file a new issue to bring in line with changes to JTS.