support creating node pools for tiflash and cdc on ack

[DanielZhangQD]

What problem does this PR solve?

fix #2378

What is changed and how does it work?

Support creating node pools for tiflash and cdc on ack.

Check List

Tests

• Manual test (add detailed scripts or steps below)
  • Deploy ACK with the following config, node pools for tiflash and cdc are created successfully and tiflash Pods can be scheduled to the tiflash nodes.

  cdc_count = 1
  tiflash_count = 1
  cdc_instance_type = "ecs.c5.large"
  tiflash_instance_type = "ecs.i2.xlarge"
  #create_cdc_node_pool = true
  #create_tiflash_node_pool = true
  

  • Deploy ACK with the following config, node pools for tiflash and cdc will not be created.

  cdc_count = 1
  tiflash_count = 1
  cdc_instance_type = "ecs.c5.large"
  tiflash_instance_type = "ecs.i2.xlarge"
  #create_cdc_node_pool = true
  #create_tiflash_node_pool = true
  

Code changes

• Has Terraform scripts change

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Does this PR introduce a user-facing change?:

Support creating node pools for TiFlash and CDC on ACK

[Yisaer]

/merge

[sre-bot]

/run-all-tests

[sre-bot]

/run-all-tests

[sre-bot]

cherry pick to release-1.1 in PR #2428