0213 hocon multiline string with indentation

[zmstone]

Fixes EMQX-11598

Release version: v/e5.6.0

Summary

• Upgrade to hocon 0.41.0 which supported multiline string with indentation.
  This is to get EMQX configuration out of escape-sequence hell for SQL programs for rule-engine.
• Stop building markdown format docs.

PR Checklist

Please convert it to a draft if any of the following conditions are not met. Reviewers may skip over until all the items are checked:

• Added tests for the changes
• Added property-based tests for code which performs user input validation
• Changed lines covered in coverage report
• Change log has been added to changes/(ce|ee)/(feat|perf|fix|breaking)-<PR-id>.en.md files
• For internal contributor: there is a jira ticket to track this change
• Created PR to emqx-docs if documentation update is required, or link to a follow-up jira ticket docs: update type descriptions emqx-docs#2365
• Schema changes are backward compatible

Checklist for CI (.github/workflows) changes

• If changed package build workflow, pass this action (manual trigger)
• Change log has been added to changes/ dir for user-facing artifacts update

example:

rule_engine {
  ignore_sys_message = true
  jq_function_default_timeout = 10s
  rules {
    a_WH_D {
      actions = ["http:a_WH_D"]
      description = ""
      enable = true
      metadata {created_at = 1707562385536}
      name = ""
      sql = """~
        SELECT
          *
        FROM
          "#",
          "$events/message_delivered",
          "$events/message_acked",
          "$events/message_dropped",
          "$events/client_connected",
          "$events/client_disconnected",
          "$events/client_connack",
          "$events/client_check_authz_complete",
          "$events/session_subscribed",
          "$events/session_unsubscribed",
          "$events/delivery_dropped"~"""
    }
    rule_rc0w {
      actions = [
        {
          args {
            mqtt_properties {}
            payload = "${.}"
            qos = 0
            retain = false
            topic = "republish-event/${clientid}"
            user_properties = ""
          }
          function = republish
        },
        {function = console}
      ]
      enable = true
      metadata {created_at = 1707389712653}
      name = ""
      sql = """~
        SELECT
          *
        FROM
          "$events/client_connected",
          "$events/client_disconnected"
      ~"""
    }
    rule_xlu4 {
      actions = [
        {function = console}
      ]
      description = ""
      enable = true
      metadata {created_at = 1706611936022}
      name = ""
      sql = """~
        SELECT
          *
        FROM
          "t/#"
      ~"""
    }
  }
}