Highlight entities not in the fgd files in the entity report list

[Outerbeast]

Option to mark entities in the entity report that don't currently exist in any fgd files used

[UnrealKaraulov]

I added it in my fork.

@wootguy need just add check if (app->fgd->getFgdClass(cname) ) then ImGui::PushStyleColor(ImGuiCol_Text, ImVec4(255, 0, 0, 255));