RESTWS-611 Use maven license plugin
* replace license.txt by file from openmrs-core/LICENSE
* added license-header.txt from openmrs-core
* use com.mycila maven license plugin
takes license-header.txt from this repo and updates .java files
* runs in root and all maven submodules
* runs by default plugin goal format which formats the headers if not properly
formatted or missing
* ATTENTION: adjusted maven profiles
had to play a trick on the "java-8" profile which uses mavens activeByDefault
this prevented the "ci" profile to run in combination with it once the env is
set to CI=true.
Now the "java-8" profile will still run by default unless you specify mvn
property
"-DnoJava8"
This however allows the "ci" profile to also be active together with the
"java-8" profile if CI=true (so for example on travis CI)
* when environment variable CI=true it will run license plugin goal "check" which
fails the build if a header is missing or not properly formatted
