feat(sysk): integrated Nari Syskeeper 2000 as a new bridge backend

[lafirest]

Fixes EMQX-10924

Summary

🤖 Generated by Copilot at 5c804a0

This pull request adds support for syskeeper forwarder and proxy, which are features that allow forwarding system metrics and events to a remote syskeeper server. It does so by adding a new application emqx_bridge_syskeeper, which contains the schema, client, frame, and proxy modules for the syskeeper protocol, and by updating the existing emqx_bridge and emqx_connector applications to include the new bridge and connector types. It also adds the license, documentation, and test files for the new application.

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