Support profanity levels

[TwiN]

Add support for multiple level of profanity detection.

e.g.

func IdProfane(s string, level int) bool {
    // ...
}

func IsProfane(s string) bool {
    return IsProfane(s, 1)
}

Where

level	description	example
1	low filter	fuck, bitch
2	moderate filter	boobs, ass
3	strict filter	adult, blood, period

* Level 2 inherits from level 1 and level 3 inherits from level 2

Note that the strict filter would have a lot of false positive, but its goal would be to prevent as much bad things from getting by as possible, even at the cost of those false positives.

The point here is that by default, the level 1 filter should be used, but if you don't trust where the strings are coming from at all, then you can scale the filter's strictness based on the level of trust.

[quackduck]

You could even let users censor based on the kind of profanity: hateful speech, simple vulgarity, etc. like https://github.com/finnbear/rustrict/blob/master/src/profanity.csv does.