Support loading profile properties from environment variables

[t1m0thyj]

Is your feature or enhancement request related to a problem or limitation? Please describe

For users of cloud IDEs or other containerized environments where the OS keyring is not easily configurable, it would be nice to support loading secure properties from environment variables.

Describe your enhancement idea

For profiles on different lpars user can have user defined env var for user and pass and refer them in the config file profile properties as "user": "$ZOWE_USER", "password": "$ZOWE_PASSWORD"

See zowe/zowe-explorer-vscode#3591 for more details

Describe alternatives you've considered

Currently I can define the ZOWE_OPT_USER and ZOWE_OPT_PASSWORD variables, but there is no way to set different per-profile properties via environment variables.

Provide any additional context

Similar to #1425, but that request was to support environment variables anywhere inside of a property value.

[github-actions]

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