some cleanup and improvements of the zeek logstash pipeline

[mmguero]

I'm going to do a couple of things to make the zeek logstash pipeline cleaner and more maintainable:

• Split the giant 11_zeek_parse.conf file up into an individual filter file for each log type
• Automatically ensure that the Zeek TSV log parsing filters (dissect and split filters) in these files are looking for TAB characters (i.e., automatically replace spaces with tabs in these filter files in case the author forgot to do so)