Add Paging Support for HTTP Endpoints

[thombergs]

Go through the HTTP endpoints and identify those that need paging.

Implement paging for these endpoints (see tutorial at https://reflectoring.io/spring-boot-paging/)

[maximAtanasov]

Paging for custom queries is in fact supported in SDN https://community.neo4j.com/t/pagination-and-sorting-with-custom-queries/1991 We should give it a shot.

EDIT: Paging does indeed work in SDN. I implemented it for the project/{id}/commits endpoint. This is what the query looks like:

  @Query(
          value = "MATCH (p)-[:CONTAINS_COMMIT]->(c) WHERE ID(p) = {0} RETURN c ORDER BY c.timestamp DESC",
          countQuery = "MATCH (p:ProjectEntity)-[:CONTAINS_COMMIT]->(c) WHERE ID(p) = {0} RETURN COUNT(c)")
  @NonNull
  Page<CommitEntity> findByProjectIdAndTimestampDescPaged(@NonNull Long projectId, @NonNull Pageable page);

I also implemented paging in the front-end and configured the paginators to load new pages on demand. However, clicking through the pages feels very sluggish and unresponsive. Considering we can load a lot of commits without pagination (maximum I've tried was 66655 commits) in a very short time and still browse them comfortably, I think we should discuss in what cases we need to page data and whether we even should.