More string filters available

Today, we've introduced three new ways of matching strings in the available filter options: "contains", "start with" and "end with". This opens up a lot more flexibility when it comes to finding patterns, for example searching emails that end with "gmail.com", IPs that start with "1.1.1" or User Agent strings containing "Firefox"

• contains will match as long as the search string can be found anywhere in the field that is being searched
• start_withwill match if the field value starts with the provided string
• end_withwill match if the field value ends with the provided string

Note that all of these filters are case-insensitive