* Fixed license header to 2020 #3154

* document import in README rather than duplicating header content

* fixed license location

* added license plugin usage in README:

* sync org with core developers in pom

* fixed exclude on class from Quartz

Bumps [maven-pmd-plugin](https://github.com/apache/maven-pmd-plugin) from 3.12.0 to 3.13.0.
- [Release notes](https://github.com/apache/maven-pmd-plugin/releases)
- [Commits](https://github.com/apache/maven-pmd-plugin/compare/maven-pmd-plugin-3.12.0...maven-pmd-plugin-3.13.0)
Signed-off-by: Ndependabot-preview[bot] <support@dependabot.com>
Co-authored-by: Ndependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>
Co-authored-by: NMarcello Teodori <151025+mteodori@users.noreply.github.com>

Bumps [maven-checkstyle-plugin](https://github.com/apache/maven-checkstyle-plugin) from 3.1.0 to 3.1.1.
- [Release notes](https://github.com/apache/maven-checkstyle-plugin/releases)
- [Commits](https://github.com/apache/maven-checkstyle-plugin/compare/maven-checkstyle-plugin-3.1.0...maven-checkstyle-plugin-3.1.1)
Signed-off-by: Ndependabot-preview[bot] <support@dependabot.com>
Co-authored-by: Ndependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

* #3129

reduce number of group ids to a single one: org.activiti

* fromatting

* add jupiter

* removed unnneeded annotations on Junit 3 tests

* revert activiti-core to junit 4

* revert activiti-spring to junit 4

When no phase is specified some of the artifacts are signed too late
Ref https://github.com/Activiti/Activiti/issues/3184

Changing the default phases is causing issues while signing artifacts (sources jars and some pom files are not signed)
Ref https://github.com/Activiti/Activiti/issues/3184

Sources artifacts are configured to be generated at deploy phase, so jar should be signed only after that.
This is also skipping the deployment for examples and conformance tests that are not required to be deployed

Ref https://github.com/Activiti/Activiti/issues/3184

Co-authored-by: Nmergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

* AAE-1113

remove Jenkinsfile and LICENCE from modules
move activiti-build parent at top level
move ide-configuration at top level
move activiti-build sub-modules to top level
fix parent references on modules to point to new top level

* AAE-1113

fix parent references on activiti-api
delete activiti-build

revert plugins versions

add developer section