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

scripts/build.sh

@@ -2,7 +2,10 @@
 
 set -eu
 
+# DEBUG returns whether DEBUG build is enabled.
+DEBUG() { [ ! -z "${DEBUG-}" ]; }
+
 CGO_ENABLED=0 go build -trimpath \
-                       -tags 'netgo osusergo static_build' \
+                       -tags "netgo osusergo static_build $(DEBUG && echo 'debugenv')" \
                        -ldflags="-s -w -extldflags '-static' -X 'main.Version=${VERSION:-$(git describe --tags --abbrev=0)}'" \
                        ./cmd/gotosocial