Improve `$genericblock` implementation

In the current implementation `$genericblock` is basically the same as `$document`, i.e. it disables filtering completely.

This implementation can be improved if we change the way the list is ordered.

Here's how the rules should be ordered:

1. Generic `css-display-none` rules
2. `$generichide` `ignore-previous-rules`
3. Generic url blocking rules
4. `$genericblock` `ignore-previous-rules`
5. Domain-specific `css-display-none rules`
6. `$elemhide` `ignore-previous-rules`
7. Domain-specific url blocking rules
8. `$urlblock` ignore-previous-rules

In addition to that `$genericblock` rules' `resource-types` should be limited and exclude `document`. In this case it will not cover cosmetic rules.

Actually, when we add [ignore-following-rules](https://github.com/AdguardTeam/SafariConverterLib/issues/87) support, it will be easier to solve it.