Take 2: Splunkbase download updates courtext res260

[Res260]

This is basically all the changes our private fork have at the moment.

Here is what it includes:

• Bugfix: bad stack trace when a test search fails
• Bugfix: add a setup step for contentctl test: wait_for_app_installation. This step ensures that the required apps are correctly installed AND configured (for splunk ES)
• Bugfix: add a 20 secs sleep after starting the container in contentctl test to ensure Docker has the time to map the ports correctly before contentctl attempts to connect. This was problematic on Windows with WSL.
• Bugfix: Fix downloading apps from SplunkBase, which used to work but didn't anymore.
• Bugfix: Fix a bug where contentctl validate and contentctl build needed the splunkbase creds to work, which made no sense.
• Fix typo
• Feature: Introduction of a logger object in the hope of gradually replacing usage of print() statements
• Feature: contentctl test now creates missing indexes specified in test data as custom_index
• Change: Send tests data to the HEC as text and not binary
• Change: Add a message that makes debugging failed tests easier.

Fixes #319 Fixes #295 Fixes #321

@pyth0n1c So sorry to open a new PR, but this was the only way for me to contribute without having to send patch files like a caveman. We should close #322 and use this PR as well. It includes a lot of changes, but I think they are all changes worthy to be included upstream and fixes weird bugs regarding using contentctl test on Windows and downloading apps from SplunkBase.

[Res260]

I will merge with main to make sure nothing breaks with the latest changes on main.

[pyth0n1c]

I will merge with main to make sure nothing breaks with the latest changes on main.

Thank you, this is great and very helpful. I will deprecate that other PR and take a look at this one!

[Res260]

I merged with main, ran my manual tests, everything is working fine on my end!