Content: Update "publishDate" metadata

[Meli-lazarte]

Description

After some testing it has been found that articles in the Bulldog Magazine have the "publishDate" field with "null" value. This is because the metadata of the articles have "date" instead of "publishDate".
In this documentation they defined the field names:
https://projects.netcentric.biz/wiki/display/VOLVOFN/OSEDS%3A+Index+Definition

If we want this to work, all the documents should contain in metadata "publishDate" instead of "date".
There are 81 articles that need to be addressed.

Notes

We need to be consistent with what has been defined in the OSEDS: Index Definition in order to avoid this kind of issues in the future.

[BeckyMedlin]

@Kannan-CM @alexiscoelho Will this require any dev work?