Add «uBlock Filters»

I know there's probably a fair few agreements between the AdGuard and uBO teams regarding the use of each others' main lists, but I still feel that https://raw.githubusercontent.com/uBlockOrigin/uAssets/master/filters/filters.txt could be considered for inclusion in AdGuard products, on the grounds that:
1) It is likely to cover many sites that haven't been reported to the "AdGuard Filters" repo yet. One of likely hundreds, or thousands, of cases is https://github.com/AdguardTeam/AdguardFilters/issues/126257
2) I can't find any previous instances on https://github.com/AdguardTeam/FiltersRegistry/issues?q=is%3Aissue+ublock+filters+ of anyone proposing adding that list yet.
3) At the time of writing, I'm unsure to which extent uBO's shorthand syntaxes (e.g. `$1p`, `$doc`, `$xhr`, `$ghide`) would be accepted by AdGuard products when used in custom filterlists, which would necessitate making it an included filterlist that makes use of https://github.com/AdguardTeam/FiltersCompiler and similar repos.