Document the meaning of metadata fields displayed in 'sample of failures' preview

[duncandewhurst]

I'm not sure how to interpret some of the metadata fields in the example below.

I don't know what version is in relation to and I can take a guess at value, result, pass_count and application_count but it would be good to have them documented.

The documentation (or a link to it) should be proximate to where the fields appear in the interface.

[jpmckinney]

Right now, we just display the internal metadata verbatim. Another option, instead of linking to documentation, is to render it in a more human-friendly way that is self-descriptive.

[jpmckinney]

As part of this, we can edit the human-readable "reason" text for clarity. See open-contracting/pelican-backend#76

[jpmckinney]

Noting that I wrote some descriptions for developers at https://pelican-backend.readthedocs.io/en/latest/tasks/checks/compiled-release.html

The meta keys should be standardized before being documented (open-contracting/pelican-backend#76).

[jpmckinney]

I think #49 and #50 are better solutions to this, as their goal is to render this raw information in an intelligible way, and require less effort from the user (no need to click on a sample first).

I improved the naming of the meta keys for clarity, as part of open-contracting/pelican-backend#76

Otherwise, for now, I added a documentation page (not linked from the UI). The keys are either clear, or can be learned once.