feat: add wait_for_commit_completion convenience method

[gustavocidornelas]

Summary

• Adds a wait_for_commit_completion convenience method.
• Usage should be:

from openlayer import Openlayer
from openlayer.lib.data.commit import wait_for_commit_completion

client = Openlayer()
commit = wait_for_commit_completion(client, "commit_id_here")

• The convenience function polls the API waiting for the commit status to be either "completed" or "failed". When "completed", returns the retrieved commit object. When "failed", raises an exception.
• The verbose kwarg (default to True) controls whether the status is print to stdout.