ProfiledPlan: expose existence for all metrics

[robsdedude]

Deprecate ResultSummary.profile of type ProfiledPlan in favor of ResultSummary.queryProfile of type Profile.

The main difference between the profile types is that the new one exposes whether stats (such as dbHits, time, etc.) have been recorded by being nullable.

According to a chat with the Cypher runtime team, the absence of the value is not equivalent to it being zero. Therefore it makes sense to express this information in the API. The information is encoded in the bolt protocol through absence or existence of the respective fields.

Closes: DRIVERS-283

Depends on:

• Improve profile and plan stub tests neo4j-drivers/testkit#705

[robsdedude]

Please don't merge yet. I'd like to wait for this work to be ready for merging across all drivers first.