XALANJ-2708 Move docs and distros generation into own profiles

The new profiles
  - 'create-docs' for Stylebook docs and
  - 'create-distros' for source and binary assemblies
are both active by default, but can be deactivated on the Maven command
line or from an IDE to achieve faster development builds, e.g. if in the
future a developer just wants to change some source code, compile and
test it. He does not need any documentation or distros for that, so he
can just build with something like:

  mvn [goal|phase] -P !create-docs,!create-distros

Relates to https://issues.apache.org/jira/browse/XALANJ-2708.
2 files changed