Plugin Developer Tools: Plugin check & fix tool

Automated tool to discover and fix common plugin faults.

https://mclear.co.uk/2020/07/18/suggestions-for-improving-etherpad-plugins/

- [x] Adds CI and updates existing travis configs.
- [x] Adds a LICENSE
- [x] Adds a .gitignore
- [x] Adds a README and checks it includes a reference to the license
- [x] Recommends translations
- [x] Checks for files that shouldn't exist and removes them (.ep_initialized, npm-debug.log)

still to do in the distant future depending on usage.
- [ ] Check packages.json includes link to github repo
- [ ] Checks Etherpad is referred to as Etherpad Lite
- [ ] Checks README includes animated gif.

bin/plugins/reTestAllPlugins.sh

@@ -0,0 +1,14 @@
+echo "herp";
+for dir in `ls node_modules`;
+do
+  echo $dir
+  if [[ $dir == *"ep_"* ]]; then
+    if [[ $dir != "ep_etherpad-lite" ]]; then
+      # node bin/plugins/checkPlugin.js $dir autofix autocommit autoupdate
+      cd node_modules/$dir
+      git commit -m "Automatic update: bump update to re-run latest Etherpad tests" --allow-empty
+      git push origin master
+      cd ../..
+    fi
+  fi
+done