Update production configurations + README for v2.3

* Refactor production nginx configuration files
* Update README for new networks, SQL, etc.

production/nginx/location-api-v1-donations.conf

@@ -0,0 +1,8 @@
+location /api/v1/donations {
+	proxy_pass https://mempool.space;
+	proxy_hide_header onion-location;
+	proxy_hide_header strict-transport-security;
+	proxy_hide_header content-security-policy;
+	proxy_hide_header x-frame-options;
+	# don't rate limit this API prefix
+}