perf(limiter): simplify the memory represent of limiter configuration

[lafirest]

Fixes EMQX-9777

1. Simplify the memory representation of the limiter configuration

Before this PR, the representation of the default limiter config in a listener is:

#{bytes => #{burst => 0.0,initial => 0,rate => infinity},
  client =>
      #{bytes =>
            #{burst => 0.0,divisible => false,failure_strategy => force,
              initial => 0,low_watermark => 0,max_retry_time => 10000,
              rate => infinity},
        connection =>
            #{burst => 0.0,divisible => false,failure_strategy => force,
              initial => 0,low_watermark => 0,max_retry_time => 10000,
              rate => infinity},
        message_routing =>
            #{burst => 0.0,divisible => false,failure_strategy => force,
              initial => 0,low_watermark => 0,max_retry_time => 10000,
              rate => infinity},
        messages =>
            #{burst => 0.0,divisible => false,failure_strategy => force,
              initial => 0,low_watermark => 0,max_retry_time => 10000,
              rate => infinity}},
  connection => #{burst => 0.0,initial => 0,rate => 100.0},
  message_routing =>
      #{burst => 0.0,initial => 0,rate => infinity},
  messages => #{burst => 0.0,initial => 0,rate => infinity}}

After this PR, there will not be any default limiter configuration representation in the memory

2. Use a container's first slot to store root/node level limiter tokens, so the root/node level can really work when the limiter configuration of a listener is omitted
3. Return the most suitable instance for different settings

Summary

🤖 Generated by Copilot at d0a7d64

This pull request refactors the emqx_limiter module and its related modules to use a shared root bucket for each limiter type, simplify the limiter configuration and schema, and improve the readability and testability of the code. It also renames some types and functions to avoid confusion and updates the test suite accordingly.

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
• Changed lines covered in coverage report
• Change log has been added to changes/{ce,ee}/(feat|perf|fix)-<PR-id>.en.md files
• For internal contributor: there is a jira ticket to track this change
• If there should be document changes, a PR to emqx-docs.git is sent, or a jira ticket is created to follow up
• 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

[coveralls]

Pull Request Test Coverage Report for Build 4881534127

• 52 of 56 (92.86%) changed or added relevant lines in 4 files are covered.
• 42 unchanged lines in 15 files lost coverage.
• Overall coverage decreased (-0.006%) to 81.612%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
apps/emqx/src/emqx_limiter/src/emqx_limiter_manager.erl	2	3	66.67%
apps/emqx/src/emqx_limiter/src/emqx_limiter_schema.erl	9	10	90.0%
apps/emqx/src/emqx_limiter/src/emqx_limiter_server.erl	40	42	95.24%

Files with Coverage Reduction	New Missed Lines	%
apps/emqx_authn/src/simple_authn/emqx_authn_http.erl	1	88.39%
apps/emqx_gateway_mqttsn/src/emqx_mqttsn_channel.erl	1	73.13%
apps/emqx_gateway/src/emqx_gateway_schema.erl	1	88.89%
apps/emqx/src/emqx_broker.erl	1	87.64%
apps/emqx/src/emqx_cm.erl	1	91.44%
apps/emqx/src/emqx_limiter/src/emqx_limiter_schema.erl	1	87.5%
apps/emqx/src/emqx_limiter/src/emqx_limiter_server.erl	1	90.91%
apps/emqx/src/emqx_alarm.erl	2	88.24%
apps/emqx/src/emqx_crl_cache.erl	2	92.31%
apps/emqx/src/emqx_limiter/src/emqx_limiter_bucket_ref.erl	2	76.47%

Totals
Change from base Build 4880440794:	-0.006%
Covered Lines:	26106
Relevant Lines:	31988

---

💛 - Coveralls