GitLab

The code removed here as been introduced in November 2015 with the initial
commit on this repository. It was during the 7.2 development, so after
4 years and 9 minor versions, it is time to remove it.

Upgrade plugins to latest available versions
Subscription edition
  - remove exclusions on bonita-web-extension declaration
  bonita-client and bonita-common are not shaded anymore in their related
  sp implementation, so dependency resolution is no directly done
  - remove duplicated servlet-api dependency declaration

This was previously used to publish artifacts to Maven Central.
The publishing process has changed, so remove the related configuration.

Compile in java 8
Use assertj 3.x and cleanup test code
Subscription: remove test dependencies as there is no test
Upgrade maven
  - maven from 3.5.2 to 3.6.0
  - wrapper from 0.4.0 to 0.4.2
  - add maven wrapper in community

* refactor(deprecation): document replacement class to use instead

Also
  - fix class header (license part)
  - remove extra keywords in interface
  - remove useless comment