Spatial 0.27.2-neo4j-4.2.3

Port of the 0.27 branch to Neo4j 4.2. This is a smaller change than the port to 4.1 and a much smaller change that that to 4.0.
Please read the release notes of those releases to understand the full scope of the changes.

For 4.2, the change was more subtle. Mostly only internal API's around the use of Path instead of File.
One change that could be noticed by users is the IndexManager.IndexAccessMode class.
In the 0.27.0 and 0.27.1 versions, we used OverridenAccessMode to take the users existing access mode and simply add on the rights to create tokens and indexes. In 0.27.2 we instead use RestrictedAccessMode to restrict the users access right to the built-in AccessModel.Static.SCHEMA and then boost to enable index and token writes.
The difference is subtle and should only be possible to notice in Enterprise Edition.