Add additional GET endpoints to user service

What does this MR do?

Adds the following endpoints to the user service

• GET /api/userlist with the parameter 'userIdList' to return user details of a list of users.
• GET /api/search with parameter 'query' to return a list of users whose name or id begins with the query

Neither of these endpoints return password or email fields. (Ignore them in the screenshots cause i cba)

Relevant screenshots

userList

search (invalid)

search (username matches)

search (lastname matches)

Testing

• Ensure the services (user / user-mongo) are uncommented in the docker compose
• Docker compose up --build
• As screenshots

Relevant issues

(List the relevant issues, i.e. Closes #...)