Explicitly set the default doi sorting parameter

[jrhoads]

Explicitly sets the default doi sorting parameter, previously this was implicitly set by passing a null or blank sort parameter to the REST API.

This is important if we ever want to change the default sorting parameter (such as in datacite/lupo/pull/1272)

Approach

Sets the default to '-updated' instead of null in relevant controllers/routes.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

• New feature (non-breaking change which adds functionality)

• Breaking change (fix or feature that would cause existing functionality to change)

Reviewer, please remember our guidelines:

• Be humble in the language and feedback you give, ask don't tell.
• Consider using positive language as opposed to neutral when offering feedback. This is to avoid the negative bias that can occur with neutral language appearing negative.
• Offer suggestions on how to improve code e.g. simplification or expanding clarity.
• Ensure you give reasons for the changes you are proposing.