Rename "com.fasterxml.jackson" -> "tools.jackson"

[cowtowncoder]

As the main task for JSTEP-1 (https://github.com/FasterXML/jackson-future-ideas/wiki/JSTEP-1) we need to:

1. Change Maven package group id from "com.fasterxml.jackson.core" to "tools.jackson.core"
2. Change Java Package name from "com.fasterxml.jackson.core" to "tools.jackson.core"

as well as all secondary changes for OSGi and Java module system.