Use caddy's certmagic library for extensible/robust ACME handling (#14177)

* use certmagic for more extensible/robust ACME cert handling

* accept TOS based on config option

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Lauris BH <lauris@nix.lv>

vendor/github.com/miekg/dns/Makefile.fuzz

@@ -0,0 +1,33 @@
+# Makefile for fuzzing
+#
+# Use go-fuzz and needs the tools installed.
+# See https://blog.cloudflare.com/dns-parser-meet-go-fuzzer/
+#
+# Installing go-fuzz:
+# $ make -f Makefile.fuzz get
+# Installs:
+# * github.com/dvyukov/go-fuzz/go-fuzz
+# * get github.com/dvyukov/go-fuzz/go-fuzz-build
+
+all: build
+
+.PHONY: build
+build:
+	go-fuzz-build -tags fuzz github.com/miekg/dns
+
+.PHONY: build-newrr
+build-newrr:
+	go-fuzz-build -func FuzzNewRR -tags fuzz github.com/miekg/dns
+
+.PHONY: fuzz
+fuzz:
+	go-fuzz -bin=dns-fuzz.zip -workdir=fuzz
+
+.PHONY: get
+get:
+	go get github.com/dvyukov/go-fuzz/go-fuzz
+	go get github.com/dvyukov/go-fuzz/go-fuzz-build
+
+.PHONY: clean
+clean:
+	rm *-fuzz.zip