Refactoring: start using rules converter for :style rules

[ameshkov]

Instead of doing it in the css-filter-rule:

            ```
            // We need this for two things:
            // 1. Convert uBlock-style CSS injection rules
            // 2. Validate pseudo-classes
            // https://github.com/AdguardTeam/AdguardForAndroid/issues/701
            var pseudoClass = parsePseudoClass(cssContent);
            if (pseudoClass !== null && ":style" === pseudoClass.name) {
                isInjectRule = true;
                cssContent = convertCssInjectionRule(pseudoClass, cssContent);
            } else if (pseudoClass !== null) {
                if (CssFilterRule.SUPPORTED_PSEUDO_CLASSES.indexOf(pseudoClass.name) < 0) {
                    throw new Error("Unknown pseudo class: " + cssContent);
                }
            }
            ```