Improve Selective Sync about cells-sync

[manuth]

Another way the schema could be reworked would be some sort of an "Action"-field to set a single action or an array of actions.
This would allow to implement more actions yet to come for single folders:

"LeftURI": "https://[...]/Documents",
"SelectiveRoots": [
    { "Path": "/", "Action": "Include" },
    { "Path": "/Keys", "Action": "Ignore (or 'Exclude')" },
    { "Path": "/Keys/KeePass", "Action": "Include" }
]

[callmelex]

I also need this feature.
But I think an ignore list ( for folders & files ) is enough, keep it simple.