[master] Enable executor properties in salt-ssh

[m-czernek]

What does this PR do?

The salt-ssh binary does not accept the module_executors and executor_opts properties, yet the salt binary does. This PR unifies the differences so that we can use the executors property for salt-ssh as well.

Previous Behavior

salt-ssh could only read the module_executors property from the roster file (minion_opts) or from the ssh_minion_opts config.

New Behavior

salt-ssh can read the module_executors property from the command-line arguments as well.

Merge requirements satisfied?

[NOTICE] Bug fixes or features added to Salt require tests.

• Docs
• Changelog - https://docs.saltproject.io/en/master/topics/development/changelog.html
• Tests written/updated

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Yes

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