use specific commit from ejabberd_tests

666fa3228ccc83bfa646157b6fbc121a86b8a288
Use new interface of pa
Add initials of generic HTTP API
Rename new API modules from ejabberd_* to mongoose_*
Dynamically decide what methods are allowed
Add initial support of POST method
Add license headers for api-related modules
Add http api handle_options callback for supported methods
Add initial support for POST and PUT
Introduce API DELETE method support