[MCHECKSTYLE-209] Correct grammar and make icons and text consistent in the report

- Do not add alternative text to icons because they are always acompanied by a text. Non-image rendering would lead into duplicate text.
- Unify output of icon and text: It is now always <icon>&nbsp;<text>
- Details table: First columns is severity and not violation
- There is no plural for information in English
- Correct spelling in German bundle

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1563620 13f79535-47bb-0310-9956-ffa450edef68