Remove uiConf type HTML5

This pull request is to remove the uiConf type for HTML5.
Not needed anymore since we now have new "config" attribute on the uiConf object.

Also need to update ```admin.ini``` on all environments to remove this line:
```
settings.uiConfTypes[] = Kaltura_Client_Enum_UiConfObjType::HTML5_PLAYER
```
 
Please review & merge