Advanced Search - Implement sorting for work items

Currently GLQL support sorting work items by the following fields https://docs.gitlab.com/user/glql/fields/#fields-to-sort-embedded-views-by.

These sorting field are being mapped to the following values on the API level:

GLQL field	ES field
created asc	created_asc
created desc	created_desc
updated asc	updated_asc
updated desc	updated_desc
health asc	health_status_asc
health desc	health_status_desc
weight asc	weight_asc
weight desc	weight_desc
closed asc	closed_at_asc
closed desc	closed_at_desc
due asc	due_date_asc
due desc	due_date_desc
milestone asc	milestone_due_asc
milestone desc	milestone_due_desc
popularity asc	popularity_asc
popularity desc	popularity_desc

Code wise the ES sorting is happening here https://gitlab.com/gitlab-org/gitlab/blob/e0c963a4dc6e2b1687769d4993a0fea0689f8a52/ee/lib/search/elastic/sorts.rb#L9-9. We need to update the existing build_sort method to support all the remaining fields from the table above.