1107 fix cluster conf sync wait loop

[zmstone]

Fixes EMQX-11329

When EMQX boots up, it tries to get latest config from peer (core type)
nodes, if none of the nodes are replying, the node will decide
to boot with local config (and replay the committed changes) if
the commit table is loaded from disk locally (an indication of the
data being latest), otherwise it will sleep for 1-2 seconds and
retry.

This lead to a race condition, e.g. in a two nodes cluster:

1. node1 boots up
2. node2 boots up and copy mnesia table from node1
3. node1 restart before node2 can sync cluster.hocon from it
4. node1 boots up and copy mnesia table from node2

Now that both node1 and node2 has the mnesia load_node pointing
to each other (i.e. not a local disk load).

Prior to this fix, the nodes would wait for each other in a dead loop.

This commit fixes the issue by allowing node to boot
with local config if it does not have a lagging.

Summary

🤖 Generated by Copilot at 7bfad34

This pull request improves the cluster configuration synchronization and booting process by using a new module emqx_cluster_rpc that provides better functions to query and update the cluster state. It also refactors and cleans up the code in emqx_conf_app and enhances the logging messages.

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
• 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