Introduce rest APIs for dynamic disk online/offline

[wsry]

Motivation

Based on the rest API, we can remove or add disk dynamically without restarting the cluster. For example, we can remove a bad disk or we can add more new disks.

Changes

New rest APIs need to be added together with the corresponding handler. In the handler, disks are removed from or added to the disk list. Both removing one disk from all ShuffleWorkers or removing one disk of a specific ShuffleWorker should be supported.

Test

• Unit test.
• Test manually on a cluster.