default settings for objectscript:sync local changes

[jasonliuspark123]

Some clients in China reported that they think put the default setting to "vscodeOnly" is more reasonable.It would be more convenient when file system level changes are made without impacting the server code.

[amelile]

Currently, the default setting is "all", after customer migrating from Studio to VSCode, their development team has experienced quite a number of unexpected scenarios in which codes in server side was mistakenly overwritten by local copy, so that they want to change the default to "vscodeOnly" or "none" instead, and also revert it back to the default value whenever detected a "all" setting, they will make the change manually when they need to.

[isc-bsaviano]

See #1783 for our reasoning for the current default. Please make any further questions on that issue.