Indexed Scripts : Add timeout

This commit adds a timeout that defaults to 5 seconds to the indexed script get operation.
It also adds a test that attempts a script get before the .scripts index is created.
When would this ever be used? Since the settings.get call above is passed a default, it would always have a value to parse right? It also feels wrong to have the default be specified multiple times (in `GetIndexedScriptRequest`, here in `SCRIPT_INDEX_OPERATION_DEFAULT_TIMEOUT`, and then again as this default passed to `parseTimeValue`).  Can they be consolidated, so there is exactly one place the default-default is specified?