Add support for env variables in executor config

[oyvinev]

It would be very useful if one were able to use environment variables when configuring an executor - an example of desired usage with the ssh executor:

executor:
   type: ssh
   config:
       user: $SSH_USER
       ip: $SSH_HOST
       password: $SSH_PASSWORD
       port: $SSH_PORT

I'm not familiar enough with Go to neither understand the complexity nor attempt a PR of it.

[halalala222]

@yohamta What do you think? I think this is a good idea.

1. Duplicate configurations can be managed by reconfiguring based on environment variables
2. This can prevent the direct exposure of sensitive information

[yohamta]

Thank you for submitting this issue and suggestions. I completely agree that this would be a valuable feature.

To implement this, we will need to make the following changes:

1. We'll add support for environment variable expansion in the executor config for all executor types available the SSH executor.
2. We'll ensure that the expanded values are not written back to the Node data, as these values contain sensitive information that shouldn't be stored in status files.

If you have any thoughts on this implementation plan or additional considerations, please feel free to share them.

[halalala222]

@yohamta Hi! I will try to work on this !

[yohamta]

Thank you @halalala222, please feel free to ask if there's any questions!

[halalala222]

@yohamta add support for environment variable expansion in the executor config for all executor types available Is it necessary to add this environment variable to executors other than the SSH executor?

[yohamta]

Hi @halalala222, I made a mistake earlier - we actually only need support for environment variable expansion in the SSH executor right now. Sorry for the confusion.

[halalala222]

@yohamta Hi!!! Thank you ! I completed this issue in this PR