[IMPROVEMENT] Check kernel module dm_crypt on host machines

[derekbit]

Is your improvement request related to a feature? Please describe (👍 if you like this request)

1. Add the necessary dm_crypt kernel module for encrypted volumes in the official document
2. Add the necessary dm_crypt kernel module check in the node.status.conditions
3. Add the necessary dm_crypt kernel module check in the longhornctl

Describe the solution you'd like

Describe alternatives you've considered

Additional context

#9135

Tasks

• doc: The documentation for the necessary dm_crypt kernel module for encrypted volumes
• longhorn-manager: dm_crypt kernel module check in the node.status.conditions
• cli: dm_crypt kernel module check

[longhorn-io-github-bot]

Pre Ready-For-Testing Checklist

• Where is the reproduce steps/test steps documented?
  The reproduce steps/test steps are at:

• CLI:

1. The command longhornctl check preflight can check if the module dm_crypt is loaded or not
2. The command longhornctl install preflight can load the module dm_crypt

• Longhorn node:

1. The node.Status.Condition ModulesLoaded will show whether the module dm_crypt is loaded or not.

• Does the PR include deployment change (YAML/Chart)? If so, where are the PRs for both YAML file and Chart?
  The PR for the YAML change is at:
  The PR for the chart change is at:
  fix(node): mount host's directory /boot/ #9374

• Have the backend code been merged (Manager, Engine, Instance Manager, BackupStore etc) (including backport-needed/*)?
  The PR is at
  cli: fix: check kernel module dm_crypt on host machines cli#66
  longhorn-manager: fix(node): add and modify node.Status.Conditions longhorn-manager#3065

• If labeled: require/doc Has the necessary document PR submitted or merged (including backport-needed/*)?
  The documentation issue/PR is at

[innobead]

Let's backport this.

[derekbit]

We need to figure out how to check the built-in kernel module. Let's move it to v1.7.2 instead.