Specify error message when Certificate URLs and passphrases don't match

[Bence1001]

Checklist

• [x] I've read and followed the Contribution Guidelines
• [X] step.yml and README.md is updated with the changes (if needed)

Version

Requires a PATCH version update

Context

• The step can take multiple Certificate URLs and passphrases, separated by pipe symbols (|).
• This can be a problem if one of the passphrases contains a pipe symbol.
• Choosing another character (or string) as a separator will not work, as there's no limitation on what character can be in a Certificate passphrase (tested this manually). These passphrases are most likely generated randomly to be secure, which increases the likelihood of random characters that match our chosen separator.
• Currently, we have no better solution for ingesting "infinitely long" list inputs. We have to recognize this as a limitation.
• Therefore, the best we can do here is provide a more informative error message.

Changes

• Specify error message when Certificate URLs and passphrases don't match, as one of the reasons could be that passphrases contain pipes.
• Added E2E test for checking if the step fails correctly in this situation.
• I did some cleanup to remove old conventions that we no longer use.

[shams-ahmed]

@Bence1001 Can you update the step.yml file as well. A sample sentence under certificate_passphrase stating the limitations..

[Bence1001]

I've regenerated the README + did some cleanup in the step.yml.