feat: New logging category for containerised runtime

[akash1810]

What does this change?

When running in a container, configure log4js to write info logs to stdout. These logs will then be processed by a sidecar, e.g. https://github.com/guardian/devx-logs/tree/main/ecs.

Why?

Application logs are useful for incident triage.

---

Closes #16264.

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[github-actions]

Deploy build 28834 of dotcom:rendering-all to CODE

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---

From guardian/actions-riff-raff.

[gu-prout]

Seen on PROD (merged by @akash1810 12 minutes and 40 seconds ago) Please check your changes!

[akash1810]

This isn't working quite as expected. It appears that when Log4JS is given an unused fileAppender, it still attempts to create a directory for the log file:

/app/server.js:149305
          throw e;
          ^

Error: EACCES: permission denied, mkdir '/var/log/dotcom-rendering'
    at Object.mkdirSync (node:fs:1350:26)
    at mkdir (/app/server.js:149293:19)
    at RollingFileStream._renewWriteStream (/app/server.js:149322:5)
    at new RollingFileWriteStream (/app/server.js:149117:10)
    at new RollingFileStream (/app/server.js:400016:5)
    at openTheStream (/app/server.js:212595:20)
    at fileAppender (/app/server.js:212615:16)
    at Object.configure (/app/server.js:212675:10)
    at /app/server.js:11243:29
    at Object.onlyOnMaster (/app/server.js:356799:50) {
  errno: -13,
  code: 'EACCES',
  syscall: 'mkdir',
  path: '/var/log/dotcom-rendering'
}