store: introduce a EntryFile object to actually access file info For now a StoreEntry match a single file, but the goal is to eventually combine multiple file in a higher level Entry, so we need to introduce this distinction and use it first.

store: use a StoreEntry object instead of tuple for store files We want to make the store return more semantic information instead of a stream of file path. To achieve this, we start with adding a simple object that hold the same information as the tuple it replace, and do a simple update to the user code to fetch and use the same information. From there, we will be able to iteratively upgrade the codebase toward better objects.

store: no longer explicitly mark the splitted index as ignored Since the fncache is going to automatically recognised it as non "normal" revlog file, we don't need to explicitly make it ignored.