Redo docker build system with buildkit+multi-stage and cache pio packages (#2338)

docker/hassio-rootfs/etc/nginx/nginx.conf

@@ -0,0 +1,33 @@
+daemon off;
+user root;
+pid /var/run/nginx.pid;
+worker_processes 1;
+# Hass.io addon log
+error_log /proc/1/fd/1 error;
+events {
+    worker_connections 1024;
+}
+
+http {
+    include /etc/nginx/includes/mime.types;
+    access_log stdout;
+    default_type application/octet-stream;
+    gzip on;
+    keepalive_timeout 65;
+    sendfile on;
+    server_tokens off;
+
+    map $http_upgrade $connection_upgrade {
+        default upgrade;
+        ''      close;
+    }
+
+    # Use Hass.io supervisor as resolver
+    resolver 172.30.32.2;
+
+    upstream esphome {
+        server unix:/var/run/esphome.sock;
+    }
+
+    include /etc/nginx/servers/*.conf;
+}