Add support for automatic syncing (Upload / Download) after an interval

[futagoza]

Currently this plugin has support for automatic syncing when the settings change or manual syncing.

Can you add a third option that allows the developer to set an interval in minutes (for example, every 15 minutes, with a minimum of 1 minute, any lower and the plugin should behave as it usually does) where the plugin should check if the settings have changed, and if so, upload the new settings.

{
    "sync.autoUpload": true,
    "sync.quietSync": true,
    "sync.syncInterval": 15
}

[shanalikhan]

I'm closing this issue in favour of #396 and #123
As i don't feel this is important once auto upload/ download performs perfectly with extensions upload/ download.