Adding option for global config PrettyPrintControlCharacters

Allows for special characters to be encoded in c style on input into rsyslog. newline becomes "\n", tab becomes "\t", etc.

This is very similar to EscapeControlCharactersOnReceive but is more in line with how some have come to expect control characters to be escaped. The config name seems slightly misleading and if anyone has a better name I would happily change it.