Value fields: remove "total"

[JachymHercher]

Value fields in OCDS often use the term "total". I am not sure what it means and I think it might be misleading, e.g. because a "total" value field might be tax-less (see #817) or represent just a single award, contract a lot from a contracting process that contains more of them.

I would suggest replacing:

• "total estimated value" with "estimated value" in tender.value
• "total value" with "value" in award.value and contract.value.

[ColinMaudry]

I think "estimated" is important, otherwise data publishers may think the field only supports a fixed value.

[jpmckinney]

@JachymHercher I support the changes to award.value and contract.value.

For tender.value, did you mean to delete "total" instead of "estimated"?

[JachymHercher]

Yes, corrected, sorry.

[JachymHercher]

(To avoid unnecessary conflicts, I will create the PR for this issue once #1208 is merged (it moves around some value fields).)