Improve CachedFetcher

[thewhaleking]

• Makes CachedFetcher compatible with a wrapper
• Allow CachedFetcher to handle methods with multiple args.
• Adds a wrapper for using CachedFetcher as you would any other cache (i.e. @functools.cached
• Replaces asyncstdlib.lru_cache with CachedFetcher in DiskCachedAsyncSubstrate
• Removes asyncstdlib as a dependency
• Fixes tests
• Replaces cache.py's print calls with logging.
• Adds new method get_runtime_for_version which is basically the internals for fetching/creating a Runtime object from init_runtime, but which can be cached by runtime version specified.