Support group id in addition to group names

Based on issue #43, we want to support both notations:

* group name first
* group id if it does not work with group name

Closes #49.
(cherry picked from commit bbb0644)
Elasticsearch dependency should be provided and not compile

Please change the Elasticsearch dependency to provided (and maybe testCompile) instead of compile and runtime.

Why? If you include the plugin in embedded Elasticsearch, and you exclude anything from the Elasticsearch dependency, it is undone by this dependency also including Elasticsearch. Therefore you have to tune both, when really this plugin only needs it as provided (since it runs with Elasticsearch or in Elasticsearch but never on its own).

Closes #48.
(cherry picked from commit 3616ed6)
Add plugin release semi-automatic script

Closes #58.
(cherry picked from commit c117c11)