match, sigh, cert, pem: Document better what files are generated, what is installed into Keychain

[janpio]

The codesigning stuff is still scary, especially if you can't "just" use match. It could help if the docs could give some additional information what files are created, what exactly is installed in the keychain etc when running the action.

Tasks here:

• Find out which actions are in this "area" additionally to the ones I mentioned above
• Look through the code of them and note down the files created etc.
• Update the documentation to e.g. have a table or something that lists the artifacts that are created and stored

[janpio]

Using those tools will probably, in the best case, already output all the relevant information after the fact , meaning it will have some output or table that contains all the stuff done and installed. This could also be a starting point.