Adds tasks that check that the all jars that we build have LICENSE.txt
and NOTICE.txt files and that the files are correct. Sets check to
depend on these task.
This is mostly there for extra parnoia because we automatically
configure all Jar tasks to include the LICENSE.txt and NOTICE.txt
files anyway. But it is quite possible to add configuration to those
tasks that would override either file.
This causes check to depend on several more things than it used to.
Take, for example, javadoc:
check depends on the new verifyJavadocJarNotice which depends on
extractJavadocJar which depends on javadocJar which depends on
javadoc, this check now depends on javadoc.
This commit moves the apache and elastic license files into a new
root level `licenses` directory and rewrites the top level LICENSE.txt
to clarify the repository has a mix of apache and elastic licensed code.
This commit adapts the license headers check to no longer look for the
ealsticsearch confidential license, but instead to look for the new
Elastic License header.
This commit makes x-pack a module and adds it to the default
distrubtion. It also creates distributions for zip, tar, deb and rpm
which contain only oss code.