=pro Exclude target directories from find in publish_samples.sh

* It found activator.properties in target directories
fix maven shade docs
=doc #3881 Change link to persistence community plugins
=clu Remove debug log noise of gossip round

* that log entry is not useful
Merge pull request #2025 from akka/wip-3881-persistence-community-patriknw

=doc #3881 Change link to persistence community plugins
=doc Links to activator and some doc improvements
=sam Switch to build.sbt in activator templates
=sam #3887 Public domain license for activator templates
Merge pull request #2024 from akka/wip-publish-samples-target-patriknw

=pro Exclude target directories from find in publish_samples.sh
Merge pull request #2026 from akka/wip-remove-gossip-debug-log-patriknw

=clu Remove debug log noise of gossip round
Merge pull request #2029 from akka/wip-sharding-activator-link-patriknw

=doc Links to activator and some doc improvements
Merge pull request #2030 from akka/wip-activator-build-patriknw

=sam Switch to build.sbt in activator templates
Merge pull request #2031 from akka/wip-3887-activator-cc0-license-patriknw

=sam #3887 Public domain license for activator templates