Copy security.encryption.master-key.path file to each TiKV/PD servers

Feature Request

To configure Encryption at Rest feature, we need to copy the master key in advance to each TiKV/PD servers manually using scp.

Why the featue is needed:
It would be very helpful if tiup can copy the master key to each TiKV/PD servers based on the security.encryption.master-key.path setting to make the setup easier.

Describe alternatives you've considered:
So far we can copy the master file using scp. At least it requires to copy the file 6 times, 3 for PD and 3 for TiKV.

Teachability, Documentation, Adoption, Migration Strategy:

Here is the sample yaml file.

pd_servers:
  - host: <PD#1>
    config:
      security.encryption.data-encryption-method: "aes128-ctr"
      security.encryption.data-key-rotation-period: "6h"
      security.encryption.master-key.type: "file"
      security.encryption.master-key.path: "/tmp/tidb-master-key"
  - host: <PD#2>
    config:
      security.encryption.data-encryption-method: "aes128-ctr"
      security.encryption.data-key-rotation-period: "6h"
      security.encryption.master-key.type: "file"
      security.encryption.master-key.path: "/tmp/tidb-master-key"
  - host: <PD#3>
    config:
      security.encryption.data-encryption-method: "aes128-ctr"
      security.encryption.data-key-rotation-period: "6h"
      security.encryption.master-key.type: "file"
      security.encryption.master-key.path: "/tmp/tidb-master-key"

tikv_servers:
  - host: <TiKV#1>
    config:
      security.encryption.data-encryption-method: "aes128-ctr"
      security.encryption.data-key-rotation-period: "6h"
      security.encryption.master-key.type: "file"
      security.encryption.master-key.path: "/tmp/tidb-master-key"
  - host: <TiKV#2>
    config:
      security.encryption.data-encryption-method: "aes128-ctr"
      security.encryption.data-key-rotation-period: "6h"
      security.encryption.master-key.type: "file"
      security.encryption.master-key.path: "/tmp/tidb-master-key"
  - host: <TiKV#3>
    config:
      security.encryption.data-encryption-method: "aes128-ctr"
      security.encryption.data-key-rotation-period: "6h"
      security.encryption.master-key.type: "file"
      security.encryption.master-key.path: "/tmp/tidb-master-key"