[misc] bump metrics module to 3.4.1

- renamed package from `metrics-sharelatex` to `@overleaf/metrics`
- drop support for statsd backend
- decaffeinate
- compress `/metrics` response using gzip
- bump debugging agents to latest versions
- expose prometheus interfaces for custom metrics (custom tags)
- cleanup of open sockets metrics
- fix deprecation warnings for header access

services/document-updater/app.js

@@ -1,4 +1,4 @@
-const Metrics = require('metrics-sharelatex')
+const Metrics = require('@overleaf/metrics')
 Metrics.initialize('doc-updater')
 
 const express = require('express')

services/document-updater/app/js/Metrics.js

@@ -1,3 +1,3 @@
 // TODO: This file was created by bulk-decaffeinate.
 // Sanity-check the conversion and remove this comment.
-module.exports = require('metrics-sharelatex')
+module.exports = require('@overleaf/metrics')

services/document-updater/package.json

@@ -18,6 +18,7 @@
     "format:fix": "node_modules/.bin/prettier-eslint $PWD'/**/*.js' --write"
   },
   "dependencies": {
+    "@overleaf/metrics": "^3.4.1",
     "@overleaf/o-error": "^3.1.0",
     "@overleaf/redis-wrapper": "^2.0.0",
     "async": "^2.5.0",
@@ -26,7 +27,6 @@
     "express": "4.17.1",
     "lodash": "^4.17.19",
     "logger-sharelatex": "^1.9.1",
-    "metrics-sharelatex": "^2.6.2",
     "mongodb": "^3.6.0",
     "request": "^2.88.2",
     "requestretry": "^4.1.0",