Add initial user-lists API endpoint

[krowvin]

Refs #1733.

Summary

This draft PR adds the first user-lists API endpoint:

• GET /user/list/{user-list-id}/members?office={office-id}

What Changed

• added UserListMembersController
• added UserListDao
• added UserListMember and UserListMembers DTOs
• wired the route into the existing user-management section of ApiServlet
• added the user-list-id controller constant

Notes

• this is the first endpoint-only commit for the user-lists feature work
• it reads from the new database objects introduced in HydrologicEngineeringCenter/cwms-database#159
• the endpoint returns member identity data including user-id, full-name, and email
• the broader model is intended to remain extensible so additional contact types can be added later without changing the core membership concept

Validation

• ./gradlew :cwms-data-api:compileJava
• compiled successfully on the Ubuntu VM against the custom user-lists database schema
• rebuilt the VM data-api container and confirmed the route appears in Swagger/OpenAPI

Follow-up

Additional endpoints will be added in separate commits, one method/endpoint at a time.

[krowvin]

Drafting until DB changes are in. Did one endpoint to start so i can check performance of the endpoints as I go.