Add support for custom metadata, new `info` and `exists` method

[grdsdev]

Is your feature request related to a problem? Please describe.
There are 2 new supported methods that needs to be added.

1. info(path: str)
2. exists(path: str)

And also the upload methods now support custom metadata to be associated with the uploaded file.

Additional context
JS: supabase/storage-js#207
Swift: supabase/supabase-swift#510

[apportunities]

Is there documentation on how to add metadata through TUS uploads?

The PR here indicates TUS is supported: supabase/storage#518

[grdsdev]

Hey @jppty we just started working on the TUS implementation for Python, yet not supported.

This is the PR if you wish to track progress: #294