Add a rule tester

[zepich]

Discussed in #39

^{Originally posted by zepich April 16, 2023}
The idea is to add a rule tester in the backend UI. With this rule tester, it is possible to test how the rules perform depending on the content you enter. With that, it's easier to optimize rules without waiting for the next spam message.

Changes

• Add a 'Tools' menu item
• Add the Rule Tester form, which allows the user to enter a value and choose its type (Text, Email address, URL, IP address, User-Agent), and if rules and rule sets should be used for the test.
• After submitting the form, the entered value will be tested with the available rules and rule sets, and the user will see the test result (which rule caught the value and the points for it).

Suggested by

• @mosparo/core-developers