[improve][ci] Add explicit GitHub Actions permissions

[lhotari]

Motivation

This is required when running GitHub Actions in a fork that has been configured with restrictive access.

• GitHub Actions workflow or job permissions.
• the default permissions

Explained in "Enforcing a policy for workflow permissions in your enterprise":

Anyone with write access to a repository can modify the permissions granted to the GITHUB_TOKEN, adding or removing access as required, by editing the permissions key in the workflow file. For more information, see permissions.

Modifications

Add explicit "permissions" to each workflow.

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete