Notify user about certificate errors

[Revertron]

The 2 types of certificate issues are added in AdguardTeam/CoreLibs#868 and we have the opportunity to notify user if there is a problem with certificates on some domain or some application is not trusting our certificate.
The user can disable HTTPS-filtering for that app or try to add server's certificate to user store.

I'm showing interest in this as I was about to raise this issue.
From Magisk 17 there has been issues with loss of root which was meant to be getting fixed in 19.2, however yesterday I lost root again, and in turn was not notified by AG of the certificate issue.

[ameshkov]

@Revertron assigned to v3.2

[TPS]

pref.notify.on.unknown.ca, right?

[ameshkov]

@TPS yep, that's right