Clean up code

[wallner]

This is a code hygene PR. It does the following things:

• remove unnecessary usages of StringBuilder in toString() methods. The compiler does that for us.
• Move almost everything to constructor injection instead of field injection.
• The NumberPadder does not need to be a @Service it doesn't have any external dependencies. This commit turns it into a normal class that is instantiated by consuming classes.
• The QueryFilterParser does not need to be a @Service it doesn't have any external dependencies. The two consuming classes create their own local variables now.

[fwilhe]

This looks good to me. I consider cleaning up the code very important. Thank you.