inetcpl: Implement LaunchSiteCertDialog on top of cryptui.CryptUIDlgCertMgr

[Juan Lang]

Hi Detlef,
I have no issue with the patch, just a question:  are you sure native
does this?  Or does it call wintrust.OpenPersonalTrustDBDialog?

I'm really not sure myself, I just recall that, when using native
inetcpl, clicking on the Certificates... button in the Content tab (in
the English locale, names are of course different in other locales)
resulted in a call to wintrust.OpenPersonalTrustDBDialog, which in
turn calls crypui.CryptUIDlgCertMgr.

Regards,
--Juan