Implement relevance score sorting for MURs

[tmpayton]

What we’re after

We should implement relevance score sorting for MURs

Related ticket(s)

(Include the tickets that either came before, after, or are happening in tandem with this new ticket)

• Research: Elasticsearch relevancy scores #5842
• Test different relevance score modes #5943

Action item(s)

(These are the smaller tasks that should happen in order to complete this work)

• Determine how would the score impact the document_highlights ordering
• Test the impact on the case score when using both keyword(document) search and respondents search

Completion criteria

(What does the end state look like - as long as this task(s) is done, this work is complete)

• [ ]

References/resources/technical considerations

(Is there sample code or a screenshot you can include to highlight a particular issue? Here is where you reinforce why this work is important)