Focal Calculation decouple from Engine

Moved focal calculations to `raster` so they can be called on Tiles
independently of the Akka engine. Also expanded the test coverage to
touch these Tile methods.
Dropped FocalOp classes

They didn’t do anything that couldn’t be done easier in a direct manner
Merge remote-tracking branch 'sidestream/extent-refactor' into focal-refactor
fixing merge conflicts
fix: NODATA now returned when there is no Mode
removed debug println
Focal Refactor 2.0, removed FocalOperation classes
fix: fencepost in GridBounds constructor from Tile
fix: overallocation for focal result when in with tile neighbors

this also includes a refactor to push GridBounds argument into the
constructors
Focal calculation objects execute on apply
fix/add: focalConway to FocalOpMethods
added default hill shade and slope arguments
fix: Focal Benchmarks
Merge pull request #2 from echeipesh/focal-refactor

Focal Operations Refactor