Mask the value of the Authorization header if debug is enabled

[rosskirkpat]

📝 Description

What does this PR do and why is this change necessary?

If LINODE_DEBUG is enabled, the resty debug returns the plain-text Authorization header value from the request. This PR ensures that the Authorization header value will be sanitized/masked if debug mode is enabled.

I also added a logger to the internal testutil package that is compliant with the resty.Logger interface.

✔️ How to Test

What are the steps to reproduce the issue or verify the changes?

Reproduce the issue: set LINODE_DEBUG when using linodego and observe a plain-text token in the debug output from resty ie. Authorization: Bearer <LINODE_TOKEN_PLAIN_TEXT>

Verify the changes: set LINODE_DEBUG when using linodego and observe a masked token in the debug output from resty (see below).

2024/05/07 12:58:21.997176 DEBUG RESTY 
==============================================================================
~~~ REQUEST ~~~
GET  /v4/linode/instances  HTTP/1.1
HOST   : api.linode.com
HEADERS:
	Accept: application/json
	Authorization: Bearer *******************************
	Content-Type: application/json
	User-Agent: linodego/dev https://github.com/linode/linodego
BODY   :
***** NO CONTENT *****
------------------------------------------------------------------------------
~~~ RESPONSE ~~~
STATUS       : 200
PROTO        : 
RECEIVED AT  : 2024-05-07T12:58:21.997154-04:00
TIME DURATION: 47.792µs
HEADERS      :
	Content-Type: application/json
BODY         :
{
   "id": 100,
   "region": "test-central",
   "label": "this-is-a-test-linode"
}
==============================================================================

How do I run the relevant unit/integration tests?

I added a new test TestDebugLogSanitization relating to these changes.

[jriddle-linode]

Nice catch thank you.

[yec-akamai]

Thank you for your contribution! Everything looks great aside from @lgarber-akamai 's comment 👍

[lgarber-akamai]

I'll be out Thursday and Friday so I'll give this my preemptive approval for once my comment has been addressed. Thanks for the contribution!

[rosskirkpat]

I'll be out Thursday and Friday so I'll give this my preemptive approval for once my comment has been addressed. Thanks for the contribution!

@lgarber-akamai When you have a minute, would I be able ant to get your sign-off on the latest commit? I believe this PR is ready to be merged now.

[lgarber-akamai]

Looks perfect, thank you!