Implement Proximity Search

[tmpayton]

What we’re after

We should implement a proximity search using intervals queries.

Related ticket(s)

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

• Research implementing proximity in legal search  #5945
• https://github.com/fecgov/openFEC/tree/test-proximity-search (test branch)

Action item(s)

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

• Refer to test branch and prior research linked above
• Add intervals queries
• Determine if we want to parse interval queries from q or create a new field

Completion criteria

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

• Proximity search is added to legal search

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)