Docker auth troubleshooting

Description

This MR is intended to fix the rate limit error (dsop/confluent/confluentinc/cp-ksqldb-server-7.3#25 (comment 1314032))

skopeo copy is currently configured as a class method and is unable to reference the ABC authfile attribute (example shown below):

In [1]: from dataclasses import dataclass
   ...: from abc import ABC
   ...: from typing import Optional
   ...: 
   ...: @dataclass
   ...: class ContainerTool(ABC):
   ...:     authfile: Optional[str] = None
   ...: 
   ...: @dataclass
   ...: class Skopeo(ContainerTool):
   ...:     def test_instance(self):
   ...:         print(self.authfile)
   ...: 
   ...:     @classmethod
   ...:     def test_class(cls):
   ...:         print(cls.authfile)
   ...: 

In [2]: sk = Skopeo(authfile="test")

In [3]: sk.test_instance()
test

In [4]: sk.test_class()
None

Testing

https://code-ib-mario.staging.dso.mil/dsop/chrome-dome/ubi8/-/pipelines/5317