Add easy steps to follow to publish new providers

[onnimonni]

Related Issue

Fixes #323.

Description

I had pretty terrible time investigating white space issues in my PASSPHRASE and GPG_PRIVATE_KEY. I ended up creating a script which ensures that everything is done properly.

I hope the script and the documented steps are useful for others as well.

Rollback Plan

• If a change needs to be reverted, we will roll out an update to the code within 7 days.

Changes to Security Controls

Are there any changes to security controls (access controls, encryption, logging) in this pull request? If so, explain.

[ansgarm]

Hi @onnimonni 👋

Thank you so much for the work you put into this and for sharing your script!
Given there are various different ways to create and manage keys, we unfortunately consider such a shell script as out of scope for this template.

Is there anything in the docs or the tutorial we use to document these steps, that you ran into that we could improve instead?