feat[confluence]: Permit passing params to Confluence client

[rehevkor5]

• This enables use of parameters such as backoff_and_retry which is important for the client to react well to rate limit (429) responses, as described in
  https://developer.atlassian.com/cloud/confluence/rate-limiting/ For available parameters, refer also to:
  https://github.com/atlassian-api/atlassian-python-api/blob/3.41.16/atlassian/rest_client.py#L48

Description

The LlamaIndex Confluence reader doesn't today permit devs to make use of many of the parameters that the underlying Atlassian Confluence Python client supports. For example, timeout, backoff_and_retry, max_backoff_seconds, and such. This change adds a client_args parameter to enable that.

New Package?

Did I fill in the tool.llamahub section in the pyproject.toml and provide a detailed README.md for my new integration or package?

• Yes
• No

Version Bump?

Did I bump the version in the pyproject.toml file of the package I am updating? (Except for the llama-index-core package)

• Yes
• No

Type of Change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Your pull-request will likely not be merged unless it is covered by some form of impactful unit testing.

• I added new unit tests to cover this change
• I believe this change is already covered by existing unit tests

Suggested Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added Google Colab support for the newly added notebooks.
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I ran make format; make lint to appease the lint gods