restructure: move bin/ and tests/ to src/

Also add symlinks from the old `bin/` and `tests/` locations to avoid
breaking scripts and other tools.

Motivations:

  * Scripts and tests no longer have to do dubious things like:

        require('ep_etherpad-lite/node_modules/foo')

    to access packages installed as dependencies in
    `src/package.json`.

  * Plugins can access the backend test helper library in a non-hacky
    way:

        require('ep_etherpad-lite/tests/backend/common')

  * We can delete the top-level `package.json` without breaking our
    ability to lint the files in `bin/` and `tests/`.

    Deleting the top-level `package.json` has downsides: It will cause
    `npm` to print warnings whenever plugins are installed, npm will
    no longer be able to enforce a plugin's peer dependency on
    ep_etherpad-lite, and npm will keep deleting the
    `node_modules/ep_etherpad-lite` symlink that points to `../src`.

    But there are significant upsides to deleting the top-level
    `package.json`: It will drastically speed up plugin installation
    because `npm` doesn't have to recursively walk the dependencies in
    `src/package.json`. Also, deleting the top-level `package.json`
    avoids npm's horrible dependency hoisting behavior (where it moves
    stuff from `src/node_modules/` to the top-level `node_modules/`
    directory). Dependency hoisting causes numerous mysterious
    problems such as silent failures in `npm outdated` and `npm
    update`. Dependency hoisting also breaks plugins that do:

        require('ep_etherpad-lite/node_modules/foo')

src/tests/ratelimit/Dockerfile.anotherip

@@ -0,0 +1,4 @@
+FROM node:alpine3.12
+WORKDIR /tmp
+RUN npm i etherpad-cli-client
+COPY ./tests/ratelimit/send_changesets.js /tmp/send_changesets.js

src/tests/ratelimit/Dockerfile.nginx

@@ -0,0 +1,2 @@
+FROM nginx
+COPY ./tests/ratelimit/nginx.conf /etc/nginx/nginx.conf

src/tests/ratelimit/nginx.conf

@@ -0,0 +1,26 @@
+events {}
+http {
+  server {
+        access_log  /dev/fd/1;
+        error_log   /dev/fd/2;
+        location / {
+            proxy_pass             http://172.23.42.2:9001/;
+            proxy_set_header       Host $host;
+            proxy_pass_header Server;
+            # be careful, this line doesn't override any proxy_buffering on set in a conf.d/file.conf
+            proxy_buffering off;
+            proxy_set_header X-Real-IP $remote_addr;  # http://wiki.nginx.org/HttpProxyModule
+            proxy_set_header X-Forwarded-For $remote_addr; # EP logs to show the actual remote IP
+            proxy_set_header X-Forwarded-Proto $scheme; # for EP to set secure cookie flag when https is used
+            proxy_set_header Host $host;  # pass the host header                                                   
+            proxy_http_version 1.1;  # recommended with keepalive connections                                                    
+            # WebSocket proxying - from http://nginx.org/en/docs/http/websocket.html
+            proxy_set_header Upgrade $http_upgrade;
+            proxy_set_header Connection $connection_upgrade;
+        }
+	}
+  map $http_upgrade $connection_upgrade {
+    default upgrade;
+    ''      close;
+  }
+}

src/tests/ratelimit/send_changesets.js

@@ -0,0 +1,22 @@
+'use strict';
+
+const etherpad = require('etherpad-cli-client');
+
+const pad = etherpad.connect(process.argv[2]);
+pad.on('connected', () => {
+  setTimeout(() => {
+    setInterval(() => {
+      pad.append('1');
+    }, process.argv[3]);
+  }, 500); // wait because CLIENT_READY message is included in ratelimit
+
+  setTimeout(() => {
+    process.exit(0);
+  }, 11000);
+});
+// in case of disconnect exit code 1
+pad.on('message', (message) => {
+  if (message.disconnect === 'rateLimited') {
+    process.exit(1);
+  }
+});

src/tests/ratelimit/testlimits.sh

@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+
+#sending changesets every 101ms should not trigger ratelimit
+node send_changesets.js http://127.0.0.1:8081/p/BACKEND_TEST_ratelimit_101ms 101
+if [[ $? -ne 0 ]];then
+  echo "FAILED: ratelimit was triggered when sending every 101 ms"
+  exit 1
+fi
+
+#sending changesets every 99ms should trigger ratelimit
+node send_changesets.js http://127.0.0.1:8081/p/BACKEND_TEST_ratelimit_99ms 99
+if [[ $? -ne 1 ]];then
+  echo "FAILED: ratelimit was not triggered when sending every 99 ms"
+  exit 1
+fi
+
+#sending changesets every 101ms via proxy
+node send_changesets.js http://127.0.0.1:8081/p/BACKEND_TEST_ratelimit_101ms 101 &
+pid1=$!
+
+#sending changesets every 101ms via second IP and proxy
+docker exec anotherip node /tmp/send_changesets.js http://172.23.42.1:80/p/BACKEND_TEST_ratelimit_101ms_via_second_ip 101 &
+pid2=$!
+
+wait $pid1
+exit1=$?
+wait $pid2
+exit2=$?
+
+echo "101ms with proxy returned with ${exit1}"
+echo "101ms via another ip returned with ${exit2}"
+
+if [[ $exit1 -eq 1 || $exit2 -eq 1 ]];then
+  echo "FAILED: ratelimit was triggered during proxy and requests via second ip"
+  exit 1
+fi