[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/clsi/app.js

@@ -6,7 +6,7 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const tenMinutes = 10 * 60 * 1000
-const Metrics = require('metrics-sharelatex')
+const Metrics = require('@overleaf/metrics')
 Metrics.initialize('clsi')
 
 const CompileController = require('./app/js/CompileController')

services/clsi/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/clsi/package.json

@@ -19,6 +19,7 @@
   },
   "author": "James Allen <james@sharelatex.com>",
   "dependencies": {
+    "@overleaf/metrics": "^3.4.1",
     "async": "3.2.0",
     "body-parser": "^1.19.0",
     "diskusage": "^1.1.3",
@@ -29,8 +30,6 @@
     "lockfile": "^1.0.4",
     "lodash": "^4.17.20",
     "logger-sharelatex": "^2.2.0",
-    "lynx": "0.2.0",
-    "metrics-sharelatex": "^2.6.0",
     "mysql": "^2.18.1",
     "request": "^2.88.2",
     "sequelize": "^5.21.5",