feat: add keyword filters for node subscription

[Wikeolf]

The implementation is somewhat crude with a high degree of code coupling, which might require consideration regarding merging. These commits primarily introduce a keyword filtering feature for node subscriptions. The aim is to address issues similar to #32 and #42, allowing users to filter out nodes that are confirmed to be unable to connect to the internet. This helps avoid problems like rule download failures during the first startup.

[7Sageer]

Thanks for contributing! The previous issue #55 seemed to mention this issue, which seems to be the real reason - nodes with true connection latency are unlikely to be so outrageous. Just now I tested the speed of the cold start, which is just a few seconds, I think that's acceptable.

Does the PR has any other functional improvement?

[Wikeolf]

Thanks for contributing! The previous issue #55 seemed to mention this issue, which seems to be the real reason - nodes with true connection latency are unlikely to be so outrageous. Just now I tested the speed of the cold start, which is just a few seconds, I think that's acceptable.

Does the PR has any other functional improvement?

I apologize for not describing the problem clearly in #42. In fact, the issue is similar to #32.

In my environment, I use keyword filtering to exclude nodes that do not connect to the Internet, such as official websites and traffic information, which are mixed into the subscription data. This approach improves the issue of rule downloads failing during the first startup. I also attempted to change the default DNS configuration, but removing the geosite did not resolve the problem.

This PR implements a feature to filter nodes in subscription information using keywords, allowing users to exclude unnecessary nodes. While this functionality is common in other subscription converters, my implementation is coupled. Whether to merge it into the mainline still requires consideration. Perhaps it should be refined further before being merged?

If you have any suggestions or alternative approaches, I would greatly appreciate them, as this solution does effectively address my issue.

[jaydong2016]

据说 singbox 使用自动选择组作为代理下载，并不会真的执行 urltest 选择最低延迟节点，只会选择组内的第一个节点作为代理节点，所以如果第一个节点不可用时，是可能会造成规则下载不来