Setup validation for parser configuration file

Given a custom parser configuration file, we should validate the content of it when service is launching.

Make the service crash with a helpful error message when:

• no parsers are written in interpreter property
• no matchCases are written in a parser
• no regex is written in a matchCase
• no xpath is written in a matchCase
• no acceptedTechnologies are written in a parser
• no acceptedMediaTypes are written in a parser

Let us know if we should add additional validation !