merge MontgomeryEquivalence into MontgomeryLadder, use in GaragDoor (… #418

Job	Run time
docker-master	1h 39m 12s
publish-standalone-dry-run	15s
test-standalone (master, dev, default)	59s
build-js-of-ocaml (master, 4.11.1)	14m 33s
build-wasm-of-ocaml (master, 4.14.1)	13m 56s
standalone-haskell (master)	53m 52s
generated-files (master)	55s
test-amd64	2h 21m 29s
validate-docker-master	35m 5s
deploy-js-wasm-of-ocaml	37s
docker-check-all	9s
	6h 1m 2s

Provide feedback