Add a new hint to disable rule conversion

[AdamWr]

Similar to https://github.com/AdguardTeam/FiltersCompiler/issues/245, but to disable rule conversion, for example: !+ NOT_CONVERT. Sometimes rules are incorrectly converted (when new scriptlet is added and filters compiler wasn't updated yet, check related issues). so I think that it would be nice to have a hint to disable rule conversion. This way we could use new scriptlets and haven't to wait for filters compiler update.

Related issues: https://github.com/AdguardTeam/FiltersCompiler/issues/260 https://github.com/AdguardTeam/FiltersCompiler/issues/266