[Tizen] Verification name of a widget entry file

This patch contains function which verify name
of the widget entry file during installation.
Table contains list of proper names of the files
has been moved to constans.

BUG=XWALK-2983
static std::vector<std::string> entry_pages;
if (entry_pages.empty()) {
+ entry_pages.push_back("index.html");
 entry_pages.push_back("index.htm");
 entry_pages.push_back("index.svg");
 entry_pages.push_back("index.xhtml");
 entry_pages.push_back("index.xht");
}