Set & Switch nodes need to be reconfigured when mappings are changed

[rsenden]

When configuring the Set and Switch nodes, the selected mapping(s) are stored using a combination of left-hand side and right-hand side value. This means that you will need to re-select the mapping(s) in the Set and Switch nodes if either the left-hand side or right-hand side of the mapping is updated in the mappings configuration.

To fix this, we probably need to generate some id for every configured mapping, and store that id in the Set/Switch configuration instead of storing the actual mapping values.