Investigate adding a config option that disables writing the .isdeploying, .deployed, .isundeploying, .undeployed files to the deployment scanner dir.

Idea is to make it possible to have multiple scanners on different nodes sharing the deployment directory, without having the markers from one interfere with another.

This may not be practical at all in reality; needs investigation.

Marker files created by the user to control deployment should still be supported.

The .failed and .pending files are a bit of a gray area that need investigation.