Mask sensitive properties on output

Use the same strategy as dependency-check, but more conservative. Any property with a sensitive looking name will now print as `***OCCLUDED***`. Closes #141 Also now: - no longer printing `clj-watson.properties` content (it might be any invalid file), rather instead, we print the properties that are found in the file - calculating the number of properties in `dependency-check.properties` by actual properties found rather than line count - no longer catching and printing an exceptions when loading `clj-watson.properties`. Load issues of this file should be exceptional and fatal. (Note also that cli now validates file existence). - printing the properties filenames - printing count of properties found for clj-watson properties; we do show the actual properties, but nice to see the count too. Users will likely especially appreciate this when 0 properties are found. - testing precedence of dependency-check settings