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/README.md

@@ -0,0 +1,37 @@
+# go-debug
+
+This library provides a very simple method for compile-time or runtime determined debug checks, set using build tags.
+
+The compile-time checks use Go constants, so when disabled your debug code will not be compiled.
+
+The possible build tags are:
+
+- "debug" || "" = debug determined at compile-time
+
+- "debugenv" = debug determined at runtime using the $DEBUG environment variable
+
+An example for how this works in practice can be seen by the following code:
+
+```
+func main() {
+	println("debug.DEBUG() =", debug.DEBUG())
+}
+```
+
+```
+# Debug determined at compile-time, it is disabled
+$ go run .
+debug.DEBUG() = false
+
+# Debug determined at compile-time, it is enabled
+$ go run -tags=debug .
+debug.DEBUG() = true
+
+# Debug determined at runtime, $DEBUG is not set
+$ go run -tags=debugenv .
+debug.DEBUG() = false
+
+# Debug determined at runtime, $DEBUG is set
+$ DEBUG=y go run -tags=debugenv .
+debug.DEBUG() = true
+```