make docker-compose easier to use (also by introducing variables and a setup script)

update Dockerfiles/Makefile for use with kopano supported build
introduce a local ldap image with some demo users
include caddy for reverse proxying
add proper documentation and remove obsolete build and push scripts

Signed-off-by: Felix Bartels <felix@host-consultants.de>

web/Caddyfile

@@ -0,0 +1,11 @@
+webapp.kopano.demo {
+
+	tls self_signed
+
+	redir / /webapp
+
+	proxy /webapp kwebapp:80 {
+		transparent
+		websocket
+	}
+}