core: allow renaming & merging of trackers with config (part 1 #8355) (#8608)
* rename site field to id in yaml indexers
* add id field in c# indexers
* use id field instead of class name in c#
Selector update, else it would also take the table header, leading in HTML errors too, like rockbox.
I don't get why if i use
```
selector: tr:has(a[href^="download2.php?id="])
```
it won't work fine either