[EFL][WK2] Add missing files to build webkit2/Efl.

[EFL][WK2] Add missing files to build webkit2/Efl.
https://bugs.webkit.org/show_bug.cgi?id=76139

Reviewed by Ryosuke Niwa.

Add missing files needed to build webkit2/Efl.

* Shared/efl/PlatformCertificateInfo.h: Added.
(WebKit):
(PlatformCertificateInfo):
(WebKit::PlatformCertificateInfo::PlatformCertificateInfo):
(WebKit::PlatformCertificateInfo::encode):
(WebKit::PlatformCertificateInfo::decode):
* UIProcess/Launcher/efl/ThreadLauncherEfl.cpp: Added.
(WebKit):
(WebKit::ThreadLauncher::createWebThread):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@114345 268f45cc-cd09-0410-ab3c-d52691b4dbfc