Add support for running profiling when debug build-tags provided (#491)

* wrap root HTTP handler in debug.WithPprof(), rearrange router.Start() to support this
* remove unused code
* set debug buildtag in build script when $DEBUG set
* update go-debug version with fixed handler
* use clone of router.srv for LE cert manager, reset server timeouts in debug
* add kim's other libraries to README

vendor/codeberg.org/gruf/go-debug/debug.go

@@ -0,0 +1,13 @@
+package debug
+
+// DEBUG returns whether debugging is enabled.
+func DEBUG() bool {
+	return debug
+}
+
+// Run will only call fn if DEBUG is enabled.
+func Run(fn func()) {
+	if debug {
+		fn()
+	}
+}