Clean up home file system on jenkins master

Mostly the stuff in there is down to me, so it's time for a cleanup.
A lot of the space is taken from backups of stuff that I took before permanently wiping it.

- **jenkins/.jenkins/userContent (27GB - needs to be kept!)**
- ~~sxa/sxa-openjdk21-pipeline-eatests (40GB)~~
- jenkins/.jenkins/secure-infra2108 (48GB) (Related to https://github.com/adoptium/infrastructure/issues/2108) (Removed tarballs for obsolete_generators, old adoptium-package-linux, sxa_jobs)
- jenkins/.jenkins/config-history (80GB - 76GB in `javaposse.jobdsl.plugin.ExecuteDslScripts` subdirectory - _EDIT: 135 as of June 2026_) Raised separately at https://github.com/adoptium/infrastructure/issues/3500
- jenkins/.jenkins/userContent-MOVED (🤷🏻 - a couple of temp things from 2023, the rest from Sept 2021)
- jenkins/sxabackups (~~62GB from March 2022 of which FULL-2022-03-30_13-39 is 26GB and~~ 34GB is a `userContent.tar`)
- ~~diskspace/deleteables - 79Gb of tarballed pipelines from the GA clearout earlier this year~~