Find alternative to HTMLParser library

**Describe the refactoring action**
The HTMLParser library used by ruta has not been maintained for over 10 years and is compiled with a very old Java version. It should be replaced by a modern and maintained dependency. JSoup would come to mind.

**Expected benefit**
* Use maintained dependencies.
* Also, this should fix an issue with using Ruta in OSGI environments related to https://issues.apache.org/jira/browse/ARIES-1219

Start by locating the HTMLParser dependency declaration and all of its usages in the Ruta codebase. Review how the parser is integrated, then evaluate the proposed JSoup replacement and verify that the dependency works in OSGi environments and removes the reported ARIES-1219 issue.

Written by the indexing model from the issue text.