Support performance trace (#32973)

1. Add a OpenTelemetry-like shim-layer to collect traces
2. Add a simple builtin trace collector and exporter, end users could
download the diagnosis report to get the traces.

This PR's design is quite lightweight, no hard-dependency, and it is
easy to improve or remove. We can try it on gitea.com first to see
whether it works well, and fine tune the details.

---------

Co-authored-by: silverwind <me@silverwind.io>

templates/admin/perftrace.tmpl

@@ -0,0 +1,13 @@
+{{template "admin/layout_head" (dict "ctxData" . "pageClass" "admin monitor")}}
+
+<div class="admin-setting-content">
+	{{template "admin/trace_tabs" .}}
+
+	{{range $record := .PerfTraceRecords}}
+	<div class="ui segment tw-w-full tw-overflow-auto">
+		<pre class="tw-whitespace-pre">{{$record.Content}}</pre>
+	</div>
+	{{end}}
+</div>
+
+{{template "admin/layout_footer" .}}