Feature - Make link checking more robust 

since verion 7.0.1

Link to Issue 486 <https://github.com/sypets/brofix/issues/486>

Make link checking more robust and make it configurable how to handle exceptions

Link checking may abort because an exception is thrown. For some severe errors, this makes sense, but there are some scenarios with minor errors where the checking should continue.

For example, if a record is deleted between fetching several records in a database query and TCA parsing, this may result in an exception in LinkParser.

Brofix always tries to perform robust checking so that small errors are just logged via the logging framework, but it is possible to change this behavior with the option behaviourOnCheckError in Extension Configuration:

1. (default) intelligent : mode where brofix decides on a case by case basis
2. continue : continue checking even in case of exceptions due to errors like these (which might obscure errors)
3. abort : always throw exception