Support changing CLI defaults in config-sync

[ilyakuz-db]

Changes

1. Support changing fields that have CLI defaults but not defined in the config
2. Support adding new tasks when task array already exists
3. Support task renaming (new field will be added, previously - error)
4. Add an explicit reset value for the queue.enabled, as remote returns it as nil when the queueing is disabled, and we can't define nil in config
5. Simplify logic with server-side defaults using reflect.DeepEqual, and move them to a separate file defaults.go
6. Remove SDK JSON marshaling round-trip, use dyn.FromTyped instead

Why

Some bugs were found after testing the feature in the workspace

Tests

Added tests for new tasks, task renames, and for CLI defaults

[ilyakuz-db]

When task_key is renamed, we create a new task with this key.

Not sure if we should try to be more clever here, potentially we could always insert at the same position where something was removed, to minimize the diff when the task_key was renamed