SpringBoot Switch Neo4j health checks to the new Neo4j driver

This commit replaces the Neo4j-OGM based health checks and metrics with new ones based on the Neo4j Java driver.

This PR cannot get merged on its own because it depends on https://github.com/spring-projects/spring-boot/pull/22299

Comment From: snicoll

I don't think that Neo4jMetrics belong here. After a discussion with @meistermeier, the plan is to move Neo4jMetrics to the Micrometer project. We will limit this PR to health checks.

Assuming the contribution to micrometer is accepted, we can resume integration of metrics in a separate issue.